Loading...

Archive

    10 November 2018, Volume 32 Issue 6 Previous Issue    Next Issue

    Orginal Article
    Research Papers
    Orginal Article
    For Selected: Toggle Thumbnails
    Orginal Article
    Map-based Cloning of Female Abortion (FA) Gene in Rice
    Feng LÜ, Qianying TANG, Qiming WANG, Hai ZHENG, Shimin YOU, Wenting BAI, Yanjia XIAO, Zhigang ZHAO, Jianmin WAN
    2018, 32(6): 519-528.  DOI: 10.16819/j.1001-7216.2018.8023
    Abstract ( )   HTML ( )   PDF (1170KB) ( )  

    【Objective】Phenotypic observation, genetic mapping and gene cloning of rice embryo sac mutants will lay a theoretical basis for recovering plant reproductive development.【Method】A female abortion (fa) mutant was obtained from ethyl methylsulfonate (EMS)-treated Ningjing 4. The embryo sacs of the wild-type and mutant were observed at different developmental stages, and the types of mutant embryo sacs were also calculated. The heterozygous mutant was used as the female parent and N22 as the male parent to construct the mapping population. The phenotype was analyzed by genetic analysis, and the target gene was precisely mapped by map-based cloning method. 【Result】Phenotypic analysis showed that the mutant’s pistil showed no difference in appearance, but the plants showed complete sterility at maturity. Compared with the wild type, the development of the mutant embryo sacs was abnormal, which could not form seven-cell eight-nuclear structure. Genetic analysis showed that the fa mutant traits were controlled by a single recessive gene. The gene was initially mapped between the L1 and L3 markers on chromosome 1 and finally between markers L10 and L11 by expanding the mapping population, with a physical distance of 117 kb. Sequencing analysis showed that LOC_Os01g68870 had a single base substitution in exon, from thymine(T) to cytosine(C), leading to amino acid change from leucine to proline and this phenotype. The results of qRT-PCR showed that compared with OsMADS13, OsAPC6 and OsTDL1A, the expression level of OsDEES1 in the mutant fa embryo sacs was the most significant, and FA might act at OsDEES1 upstream. Subcellular localization showed that the FA protein is localized to the plasma membrane. 【Conclusion】 According to the present study, FA gene was a new allele of MSP1. Our work further elucidates the importance of this gene in the development of embryo sacs and provides new clues in regulation the network system.

    Genetic Mapping and Proteomic Analysis of the Dwarf and Low-tillering Mutant dlt3 in Rice
    Minjuan ZHANG, Shuaijun LI, Qiongqiong CHEN, Xiuqing JING, Kunming CHEN, Chunhai SHI, Wenqiang LI
    2018, 32(6): 529-537.  DOI: 10.16819/j.1001-7216.2018.8001
    Abstract ( )   HTML ( )   PDF (1011KB) ( )  

    【Objective】Plant height is an important agronomic trait for crops because dwarf cultivars are more resistant to lodging. Many factors are responsible for dwarfism in plants, but gibberellin (GA) and brassinosteroid (BR) are the most intensely studied factors, since their molecular mechanism in regulating plant height is important for both basic and applied researches of plant breeding. 【Method】In the present study, we reported the characterization and genetic mapping of a dwarf and low-tillering mutant, dlt3, gained through gamma ray mutagenesis of O. sativa indica 9311. The agronomic traits of the dlt3 mutant including plant height, tiller number, lamina inclination, leaf length and width, and seed-setting rate were analyzed by morphological observation and statistics. The responses to GA and BR were detected based on the changes of leaf angle by exogenous application of BR and GA-induced α-amylase activity. The F2 population and molecular markers were used for genetic mapping of the dlt3 gene. Furthermore, isobaric tags for the relative and absolute quantitation (iTRAQ)-based proteomic method were applied to determine the proteomics of the dlt3 mutant as compared with wild type. 【Result】The plant height, tiller number, leaf angle, leaf length and seed-setting rate were significantly reduced in dlt3. The mutant also showed increased width of leaf blades, dark green and crinkled leaves. The mutant showed normal response to GA, but no response to exogenous BR. Genetic analysis revealed that the dlt3 phenotype was controlled by a single recessive nuclear gene. The dlt3 gene was mapped on the short arm of chromosome 6 between molecular markers RM2615 and R6M14. The iTRAQ-based proteomic analysis revealed that a total of 330 proteins were differentially expressed in the dlt3 mutant, including 222 up-regulated proteins and 108 down-regulated proteins. It showed that four proteins were directly involved in BR signaling pathway and several proteins involved in plant height and developmental regulation were differentially expressed in the mutant. Furthermore, many proteins especially some kinase and phosphatase related proteins, Ca2+ binding related proteins and zinc finger containing proteins were significantly enriched in the mutant. 【Conclusion】These results indicate that the dlt3 is a BR-insensitive dwarf and low-tillering mutant. The DLT3 locus, whose mutation results in abnormal BR signaling, could play important roles in regulating both plant height and other aspects of rice growth and development.

    Identification and Gene Mapping of White Stripe Leaf and White Panicle Mutant wlp6 in Rice
    Lingfeng LI, Yuyi XIONG, Linjuan OUYANG, Xiaosong PENG, Xiaorong CHEN, Xiaopeng HE, Junru FU, Jianmin BIAN, Lifang HU, Jie XU, Haohua HE, Xiaotang SUN, Changlan ZHU
    2018, 32(6): 538-548.  DOI: 10.16819/j.1001-7216.2018.7144
    Abstract ( )   HTML ( )   PDF (1021KB) ( )  

    【Objective】Leaf color mutants are important materials for studying the regulation of photosynthesis, chlorophyll biosynthesis and genetic development in rice. The discovery of leaf color mutants is an important genetic basis for functional genomics research in rice. 【Method】 A mutant of white stripe leaf and white panicle was found in Changhui 121, which could be inherited stably to successive generations, and temporarily termed wlp6 (white striped leaf and panicle 6). wlp6 and wild-type seeds were seeded in the early, middle and late seasons in Nanchang, Jiangxi Province and the agronomic traits of the middle and late rice were investigated. Chlorophyll contents in leaf and glume at the 3-leaf stage, tillering stage and heading stage were tested. The development of mesophyll cells at the heading stage was observed with a electron microscopy. Temperature and light sensitive experiments were carried out in an illumination incubator. The phenotype of reciprocal F1 between wlp6 and Changhui 121, 02428 was observed and chi-square test was conducted on F2 segregating population to analyze the genetic pattern of the mutant. The F2 population derived from wlp6/02428 was used as material, and the mapping was carried out by the BSA method. 【Result】 From 1-leaf stage to mature stage, all leaves of wlp6 showed white stripes. At the heading stage, glumes and branches were albino, and the panicle turned green under high temperature. The plant height, number of effective panicles and number of grains per panicle of the mutant were significantly lower than those of its wild type in the two seasons, and the seed-setting rate and 1000-grain weight of wlp6 in late season were also significantly lower. The leaf chlorophyll contents of wlp6 were significantly lower than those of the wild type at all growth stages. The husk chlorophyll contents of wlp6 were significantly lower than those of the wild type in early and late season. In wlp6, the number of chloroplasts decreased, the volume became smaller, and there was no obvious lamellar structure. Leaf chlorophyll contents increased with the temperature and sunshine duration increase. Genetic analysis showed that the trait was controlled by recessive nuclear genes. WLP6 was located in the interval InDel markers R-7-R-8(physical distance 137 kb), on the short arm of chromosome 6. In this interval, 21 candidate genes were predicted. Through the analysis of candidate genes and sequencing, we found that LOC_Os06g14620 encodes a small chain of RNA reductase, 142nd and 158th base of the coding region carried a substitution from T to C, and the base A was inserted at the 288th position. The insertion of the base leads to termination of the gene translation. Therefore, it is speculated that LOC_Os06g14620 is the candidate gene for WLP6.【Conclusion】LOC_Os06g14620 is the candidate gene of the cloned white stripe gene St1. WLP6 is the allele of St1, with different mutation sites and phenotypes.

    Overexpression of Sucrose Transporter OsSUT1 Affects Rice Morphology and Physiology
    Bing FENG, Yafei SUN, Hao AI, Xiuli LIU, Jing YANG, Lu LIU, Feiyan GAO, Guohua XU, Shubin SUN
    2018, 32(6): 549-556.  DOI: 10.16819/j.1001-7216.2018.8015
    Abstract ( )   HTML ( )   PDF (973KB) ( )  

    【Objective】Phosphorus exerts an important influence on synthesis of sucrose and starch in plant cell. There are still many aspects need to be clarified about their relationship.【Method】In this study, OsSUT1-overexpressed material was obtained by using transgenic technology. Effects of overexpression of this gene on sucrose and phosphorus contents, as well as plant morphology and physiology were investigated under hydroponics and pot experiment conditions. 【Result】Expression analysis at the transcription level indicated that OsSUT1 was induced by phosphorus deficiency in rice roots. Hydroponics experiment showed that compared with the wild-type plant, over-expression of OsSUT1 in the transgenic plant under normal phosphorus supply resulted in a decrease in sucrose content in shoot and an increase in phosphorus content in both root and shoot. However, there was no significant difference in sucrose and phosphorus contents between the OsSUT1-overexpressed and control plants under phosphorus deficiency conditions. Pot experiment showed that overexpression of OsSUT1 increased the number of tillers, effective tillers, and phosphorus content in rice, and the seed size was also larger than that of the wild type. 【Conclusion】These results indicate that OsSUT1 influences sucrose and phosphorus contents and growth and development of the transgenic rice.

    Agronomic Traits of Marker-free Transgenic japonica Rice with Overexpression of OsPHF1 Under Low Phosphorus Environment
    Zhanghua HU, Xiuyan LIU, Yufeng WANG, Yu PENG, Xiaoliang SHI, Sheng TENG
    2018, 32(6): 557-564.  DOI: 10.16819/j.1001-7216.2018.8034
    Abstract ( )   HTML ( )   PDF (773KB) ( )  

    【Objective】PHF1 (phosphate transporter assistance factor) regulates specific phosphorous transporters after transcriptional regulation and affects the utilization efficiency of phosphate. The main purpose is to develop selective-marker-free OsPHF1-overexpressed japonica rice (Kongyu 131), and study the agronomic traits of transgenic rice at different low phosphorus concentrations. It contributes to the cultivation of transgenic rice varieties with high phosphorus utilization efficiency.【Method】Marker-free OsPHF1-overexpressed transgenic lines were obtained by using double T-DNA methods, Agrobacterium-mediated infection and subsequent screening. The field experiments for T3 and T4 generations of transgenic plants were carried out under low phosphorus concentration (75 or 112.5 kg /hm2 calcium superphosphate) medium-to-low phosphorus concentrations (225 or 300 kg /hm2 calcium superphosphate) and normal phosphorus concentration (450 kg /hm2 calcium superphosphate).【Result】Three marker-free homozygous transgenic lines F18-18, F22-32 and F25-6 were obtained. The expression levels of OsPHF1 in lines F22-32 and F25-6 were much higher than that of wild type. Field experiments showed that compared with the wild type, the tiller number of F22-32 and F25-6 (T3 generation) were increased by 55% and 25%, respectively and the yield per plant of F22-32 and F25-6 were increased by 38%–34%, respectively under medium-to-low phosphorus environment (300 kg/hm2 calcium superphosphate). The yield of F22-32 and F25-6 transgenic lines (T4) increased by 30% to 35%, the biggest improvement under low phosphorus (112.5 kg /hm2 calcium superphosphate). Meantime, the tiller number and yield of F22-32 and F25-6 (T4) also showed obvious boost under medium-to-low phosphorus (225 kg /hm2 calcium superphosphate) levels. 【Conclusion】Marker-free OsPHF1 transgenic lines were cultivated using double T-DNA method. Two generation of homozygous transgenic lines showed significantly increased tiller number and yield at medium-to-low phosphorus level (112.5, 225 or 300 kg /hm2 calcium superphosphate).

    Analysis on Evolution of Major Rice Cultivars in China
    Hai LIN, Tingting LI, Hanhua TONG, Zhigang WANG, Lei WANG, Zhiguo E
    2018, 32(6): 565-571.  DOI: 10.16819/j.1001-7216.2018.8107
    Abstract ( )   HTML ( )   PDF (1275KB) ( )  

    【Objective】Wide application of improved varieties is an important measure to develop high-yield, good quality and high-efficiency agriculture. It means that old varieties are replaced by new ones, namely, variety evolution. The insight into the evolution pattern of varieties not only helps understand the breeding history, but also provides a reference for breeding and supervision. We developed an algorithm for objective calculation of the replacement pattern of rice varieties in this study. 【Method】Based on the ASP. net platform and VB. net syntax, a program was compiled to analyze the rice variety data collected in SQL Server 2008 database, and the general rules of rice variety evolution in China in the past 30 years were obtained. 【Result】Program analysis shows that the average annual replacement rate of rice varieties is about 11.1% based on the area change algorithm, and 29.7% based on the variety number change algorithm. 【Conclusion】In rice production in China, the improved varieties have been replaced at a faster rate for a long time. The reasons for the high rate of varieties succession are analyzed, and some suggestions are put forward to improve the breeding efficiency.

    Response of Yield and Quality of Double-cropping High Quality Rice Cultivars Under Free-air Temperature Increasing
    Taotao YANG, Qixing HU, Shan HUANG, Yanhua ZENG, Xueming TAN, Yongjun ZENG, Xiaohua PAN, Qinghua SHI, Jun ZHANG
    2018, 32(6): 572-580.  DOI: 10.16819/j.1001-7216.2018.8050
    Abstract ( )   HTML ( )   PDF (782KB) ( )  

    【Objective】Rice is an important food crop in China, thus it is very important for food security to clarify the influence of global warming on the yield and quality of double-cropping high quality rice cultivars. 【Method】A free air temperature increasing facility (FATI) was constructed in a double-cropping rice system with Jinzao 47 (indica inbred) and Liangyou 287 (indica hybrid) as early rice and Xiangyaxiangzhen (indica inbred), Wanxiangyouhuazhan (indica hybrid) and, Yongyou 5550 (japonica hybrid) as late rice. The responses of rice yield, yield components, and grain quality to warming were determined. 【Result】The effect of warming (1.3℃–1.6℃) on the yield of early and late indica rice was not significant, but the yield of late japonica cultivar decreased by 10.2% mainly due to the decrease in grain number per panicle. Under FATI, the plant height of both early and late rice decreased. The growth duration of early rice was shortened by 3–4 days under warming, while that of the late rice did not change significantly. Warming significantly increased the chalky grain percentage and chalkiness for both early and late rice. The brown rice percentage of Liangyou 287 and the head rice percentage of both Liangyou 287 and Yongyou 5550 were significantly increased by warming. The protein content of late rice was significantly increased by warming, whereas the amylose content of late japonica rice showed the opposite trend. In contrast, both the protein and amylose contents of early rice were not significantly affected by warming. The characteristic values of RVA of rice varied with cropping seasons and cultivars. 【Conclusion】Warming exerted a greater influence on the yield of high quality late japonica rice than that of indica rice. Increasing temperature could improve the milling quality, but decrease the appearance quality. Late rice was more sensitive to warming in nutrition quality and eating quality as compared with early rice.

    Effects of Weak Light Stress at Different Stages on Sink-source Characteristics and Protective Enzyme Activities in Leaf of Late Rice Varieties with Different Tolerance
    Kang LUO, Yongjun ZENG, Qixing HU, Le CHEN, Yanhong YI, Feng SUI, Xing LI
    2018, 32(6): 581-590.  DOI: 10.16819/j.1001-7216.2018.7146
    Abstract ( )   HTML ( )   PDF (818KB) ( )  

    【Objective】The purpose of this study is to clarify the differences in sink-source characteristics and leaf protective enzyme activities of late rice with different tolerance to weak light stress, so as to reveal its tolerance mechanism, and lay a theoretical basis for the selection of new rice varieties with high and stable yield and stress-resistance cultivation.【Method】In order to reveal the effects of weak light stress at different stages on sink-source characteristics and leaf protective enzyme activities in late rice with different tolerance to weak light stress, two late rice were grown with shading at different stages. 【Result】The results showed that weak light stress at different stage exerted great influence on the growth of late rice. Shading at tillering stage decreased tiller number, grain number per panicle and total spikelet number, as well as leaf area and yield. Shading at panicle initiation stage decreased tiller number, grain number per panicle, total spikelet number, leaf area, seed setting rate and the yield. Shading at filling stage reduced the net assimilation rate of leaf, seed setting rate, 1000-grain weight and yield. Weak light stress had a greater influence on the source of late rice than on the sink. The effects of weak light stress on the yield of late rice were as follows: filling stage > PI stage > tillering stage. 【Conclusion】Under weak light stress, the type with strong tolerance could offset the decline of leaf area by increasing leaf length and width, maintaining relatively optimum leaf nitrogen content, and higher protective enzyme activities such as superoxide dismutase(SOD) and catalase(CAT) and a stabilized peroxide(POD) activity in leaf with slight drops in net assimilation rate, strong “source” ability and less yield reduction rate. The stronger capability of leaf area compensation and nitrogen content maintaining, and higher level of protective enzyme activities in leaf are accountable for higher tolerance to weak light stress for rice.

    Senescence-specific Changes in Endogenous IAA Content and Its Conjugated Status in Rice Flag Leaf as Affected by Nitrogen Level
    Hua ZHAO, Fubiao WANG, Zhanyu HAN, zakari SHAMSU-ADO, Zhaowei LI, Gang PAN, Fangmin CHENG
    2018, 32(6): 591-600.  DOI: 10.16819/j.1001-7216.2018.8028
    Abstract ( )   HTML ( )   PDF (1155KB) ( )  

    【Objective】 The objective is to clarify the genotype-dependent alteration in rice leaf senescence process and its relationship with the endogenous IAA content and its conjugated status in flag leaves during filling stage, and also to investigate the effect of N supply levels on leaf senescence and its relation to the endogenous IAA content and its conjugated status in leaves for different rice genotypes. 【Method】 Two rice genotypes, namely, the premature senescence mutant in flag leaf (psf) and its wild type (Zhehui 7954), were used to compare their difference in the temporal patterns of IAA content and its conjugated status as well as transcriptional expression of YUCCAs family genes in flag leaf during filling stage. Three N levels, including low nitrogen level (LN, 1.45 mmol/L), normal nitrogen level (MN, 2.9 mmol/L), and high nitrogen level (HN, 5.8 mmol/L), were designed to examine the response of IAA content and its conjugated status in senescent leaves to different N supply levels. 【Result】The free IAA content in the flag leaf of psf mutant was significantly lower than that of its wild type during leaf senescence, while the opposite was true for the genotype-dependent alteration in the conjugated status IAA (IAA-ASP) content in senescent leaves, with a markedly higher level and more rapidly increase of IAA-ASP content in the flag leaf of psf mutant relative to its wild type along with leaf senescence. Among 7 YUCCAs isoform genes related to IAA biosynthesis, the transcriptional expressions of YUCCA2, YUCCA3, YUCCA4 and YUCCA6 were relatively lower in the flag leaf of psf mutant compared with its wild type, with the down-regulated temporal pattern during leaf senescence, regardless of rice genotypes. However, the transcript amount of YUCCA7 in senescent leaves increased markedly from 0 to 21 days post anthesis, followed by a declining level of transcriptional expression at the late stage of leaf senescence process. This result implied that the rapid decrease in chlorophyll contents and also its accelerated leaf senescence symptoms for psf mutant were partly attributable to the weaker IAA biosynthesis in psf leaves during leaf senescence, in which the transcriptional level of YUCCA7 expression might play an important role in the regulation of IAA biosynthesis in senescent leaves; the effect of N supply on the endogenous IAA content and its conjugated status in rice leaves was greatly variable, depending on the stage of leaf senescence. At the initial and early stages of leaf senescence, LN treatment decreased the free-IAA content in rice leaves and increased the IAA-ASP content in rice leaves, while HN resulted in a marked increase in free-IAA content in the senescent leaves, with a significant decrease in IAA-ASP content under HN. Comparatively, HN treatment displayed lower level in both free-IAA and IAA-ASP contents than NN an LN treatment at the late stage of leaf senescence (for psf mutant at about 28 day post anthesis) with severe leaf senescence symptom【Conclusion】The onset and progression of leaf senescence were closely associated with IAA content and its conjugated status in rice leaves. The markedly increased IAA-ASP content in rice leaves may be considered as one of most important reasons for the accelerating progression of leaf senescence symptom, and HN-induced decrease in IAA-ASP content in rice leaves was, at least partly, responsible for the delay of leaf senescence progression.

    Carbon Footprint Analysis of Double Cropping Rice Production in the Middle Yangtze River Valley Based on Household Surveys
    Zhongdu CHEN, Chunchun XU, Long JI, Fuping FANG
    2018, 32(6): 601-609.  DOI: 10.16819/j.1001-7216.2018.7080
    Abstract ( )   HTML ( )   PDF (676KB) ( )  

    【Objective】The middle Yangtze River Valley is one of the major double cropping rice areas in China, and it is of great significance to analyze the carbon footprint of double cropping rice for developing low-carbon agriculture in this region.【Method】According to a survey on farmers, the carbon footprint of double rice production in the middle Yangtze River Basin was estimated using a life-cycle assessment method in the agricultural sector. The proportion of different agricultural inputs in the carbon footprint of double cropping rice production was explored. In addition, the relationships between fertilizer and irrigation inputs and the double cropping rice yield, carbon footprint and the rice grain yield were analyzed.【Result】The results showed carbon footprint per unit yield, carbon footprint per unit biomass and carbon footprint per unit production value for double rice in the middle Yangtze River Valley were 0.67 kg /kg, 0.35 kg/kg and 0.27 kg/CNY, respectively, showing a significant decrease with the increase of double yield. The main components of the carbon footprint were CH4 (66.2%), Diesel consumption (13.2%) and fertilizer (10.9%). With low grain yield, 22.4% early rice field and 36.7% late rice field were found excessively-fertilized, and 28.4% and 33.5% were excessive in irrigation. There were large potentials in energy saving and emission reduction. A decrease of carbon footprint in early rice and late rice was found in large-sized farms by 29.7% and 37.2%, respectively, compared to smaller ones. This study demonstrated that carbon footprint of crop production could be affected by farm size and climate condition as well as crop management practices.【Conclusion】 Thus, moderate reduction of double-cropping rice area and developing technology that saves water and fertilizer, as well as conservation tillage technology and large scaled farms could help mitigate greenhouse gas emissions from double-cropping rice production of the middle Yangtze River Valley.

    Research Papers
    Carbon Footprint Analysis of Double Cropping Rice Production in the Middle Yangtze River Valley Based on Household Surveys
    CHEN Zhongdu, XU Chunchun, JI Long, FANG Fuping*
    2018, 32(6): 601-609.  DOI: 10.16819/j.1001-7216.2018.7080
    Abstract ( )   HTML ( )   PDF (1043KB) ( )  

    【Objective】The middle Yangtze River Valley is one of the major double cropping rice areas in China, and it is of great significance to analyze the carbon footprint of double cropping rice for developing low-carbon agriculture in this region.【Method】According to a survey on farmers, the carbon footprint of double rice production in the middle Yangtze River Basin was estimated using a life-cycle assessment method in the agricultural sector. The proportion of different agricultural inputs in the carbon footprint of double cropping rice production was explored. In addition, the relationships between fertilizer and irrigation inputs and the double cropping rice yield, carbon footprint and the rice grain yield were analyzed.【Result】The results showed carbon footprint per unit yield, carbon footprint per unit biomass and carbon footprint per unit production value for double rice in the middle Yangtze River Valley were 0.67 kg /kg, 0.35 kg/kg and 0.27 kg/CNY, respectively, showing a significant decrease with the increase of double yield. The main components of the carbon footprint were CH4 (66.2%), Diesel consumption (13.2%) and fertilizer (10.9%). With low grain yield, 22.4% early rice field and 36.7% late rice field were found excessively-fertilized, and 28.4% and 33.5% were excessive in irrigation. There were large potentials in energy saving and emission reduction. A decrease of carbon footprint in early rice and late rice was found in large-sized farms by 29.7% and 37.2%, respectively, compared to smaller ones. This study demonstrated that carbon footprint of crop production could be affected by farm size and climate condition as well as crop management practices.【Conclusion】 Thus, moderate reduction of double-cropping rice area and developing technology that saves water and fertilizer, as well as conservation tillage technology and large scaled farms could help mitigate greenhouse gas emissions from double-cropping rice production of the middle Yangtze River Valley.

    Orginal Article
    Screening for Strains of Rice Spikelet Rot Disease Pathogenic Fungus with High Fumonisin Production and Strong Pathogenicity
    Lei SUN, Ling WANG, Lianmeng LIU, Yuxuan HOU, Qiqin LI, Shiwen HUANG
    2018, 32(6): 610-616.  DOI: 10.16819/j.1001-7216.2018.8045
    Abstract ( )   HTML ( )   PDF (918KB) ( )  

    【Objective】 The objective is to develop a stable and efficient artificial inoculation technique to identify the pathogenicity of different strains for rice spikelet rot disease (RSRD), and to test the ability of F. proliferatum to synthesize fumonisin in two culture media by detecting and analyzing the contents of fumonisin. Based on the methods, strains with high fumonisin production and strong pathogenicity were selected. 【Method】 Injection and spraying inoculation methods were adopted at booting and heading stages. The pathogenicity and stability of different inoculation methods at different growing stage of rice were investigated. The pathogenicity and the ability of fumonisin production of different strains were investigated by using suitable inoculation methods and HPLC-MS/MS analysis. 【Result】 The incidence of RSRD is high and stable with injection inoculation at pollen mother cell meiosis to maturing stages, and rice grain yield was significantly affected by inoculation during pollen mother cell formation to initial heading stage. The high pathogenic strains FP4, FP6, FP8, FP9 and FP10 were selected based on injection inoculation. The fumonisin synthesis assaying was conducted by using HPLC-MS/MS, and the strains FP4 and FP9, with high fumonisin production and strong pathogenicity were identified finally. The culture media made of rice grains was more suitable than that making of corn for fumonisin synthesis.【Conclusion】 The invasion period of F. proliferatum of RSRD was pollen mother cell formation to full heading stage, the initial infection stage was pollen mother cell formation to meiosis stage, and the effect of RSRD on rice yield was closely related to infection stage.