以籼稻9311为背景的水稻突变体中发现一个黄绿叶突变体(yellowgreen leaf, ygl10)。形态分析表明，与野生型9311相比，ygl10突变体株高、穗长降低，结实率下降。叶绿素含量测定表明，ygl10突变体中叶绿素a、叶绿素b和类胡萝卜素含量均极显著降低，其中叶绿素b降幅最大，只有野生型的2%。叶绿体超微结构观察表明，突变体中类囊体和基粒片层数量明显减少。遗传分析结果表明，该黄绿叶突变体由一隐性核基因控制。进一步利用分子标记将ygl10定位在水稻第10染色体约380 kb的区段内。对该区段内存在的ORF进行序列分析，发现编码叶绿素a氧化酶（chlorophyll a oxygenase）基因（OsCAO1）的第9个外显子存在5个碱基缺失，从而导致提前出现终止密码子，推测CAO1即为ygl10的候选基因。
A rice mutant characterized by yellowgreen leaves (named as ygl10) was obtained from an indica cultivar 9311 via radiation of 60Coγ ray. Morphological analysis showed that, the ygl10 mutant exhibited shorter plant height and panicle length, decreased seed setting rate compared to its wild type (9311). Moreover, the chlorophyll content in the ygl10 mutant leaves dramatically decreased, especially for chlorophyll b content, being only about 2% of that in its wild type. In addition, the SEM results showed that the numbers of grana lamella, and thylakoids in the mutant were less than those in the wild type. Genetic analysis and gene mapping showed that the yellow green leaf mutant was controlled by a single recessive gene, which was located in a 380 kb region on chromosome 10. We further analyzed the putative candidate open reading frames in the target region through sequencing, and the results showed that there was a 5nucleotide deletion in the ninth exon of CAO1 gene (encoding chlorophyll a oxygenase involved in the biosynthesis of chlorophyll b), resulting in the frame shift to generate a new premature stop codon. Therefore, it is deduced that CAO1 is the candidate of ygl10.
\[1\]胡忠, 彭丽萍, 蔡永华. 一个黄绿色的水稻细胞核突变体. 遗传学报, 1981, 8(3)： 256261.
\[2\]Ghirardi M L, Melis A. Chlorophyll b deficiency in soybean mutants： Ⅰ. Effects on photosystem stoichiometry and chlorophyll antenna size. Biochim Biophys Acta, 1988, 932: 130137.
\[3\]Greene B A, Allred D R, Morishige D T, et al. Hierarchical response of light harvesting chlorophyllproteins in a lightsensitive chlorophyll bdeficient mutant of maize. Plant Physiol, 1988, 87(2): 357364.
\[4\]Krol M, Spangfort M D, Huner P A, et al. Chlorophyll a/bbinding proteins, pigment conversions, and early lightinduced proteins in a chlorophyll bless barley mutant. Plant Physiol (Rockville), 1995, 107(3):873883.
\[5\]Falbel T G, Meehl T B, Staehelin L A. Severity of mutant phenotype in a series of chlorophylldeficient wheat mutants depends on light intensity and the severity of the block in chlorophyll synthesis. Plant Physiology (Rockville), 1996, 112(2): 821832.
\[6\]Falbel T G, Staehelin L A. Partial blocks in the early steps of the chlorophyll synthesis pathway: A common feature of chlorophyll betadeficient mutants. Physiol Plant, 1996, 97(2): 311320.
\[7\]Zhao Y, Du L F, Yang S H, et al. Chloroplast composition and structural differences in a chlorophyllreduced mutant of oilseed rape seedlings. Acta Bot Sin, 2001, 43(8): 877880.
\[8\]邓晓娟, 张海清, 王悦， 等. 水稻叶色突变基因研究进展. 杂交水稻, 2012， 27(5)： 914.
\[9\]Beale S I. Green genes gleaned. Trends Plant Sci, 2005, 10(7): 309312.
\[10\] Lichtenthaler H K. Chlorophylls and carotenoids: Pigments of photosynthetic biomembranes. Methods Enzymol, 1987, 148: 350382.
\[11\]周青山, 周广洽, 谢锦云, 等. 高温对杂交水稻“威优六号”叶绿体超微结构和生理活性的影响. 湖南师范大学学报：自然科学版, 1981(1)：4548
\[12\]Murray M G， Thompson W F. Rapid isolation of high molecular weight plant DNA. Nucleic Acids Res, 1980, 8(19): 43214325.
\[13\]Lee S, Kim J H, Yoo E, et al. Differential regulation of chlorophyll a oxygenase genes in rice. Plant Mol Biol, 2005, 57(6): 805818.
\[14\]Mueller A H, Dockter C, Gough S P, et al., Characterization of mutations in barley fch2 encoding chlorophyllide a oxygenase. Plant Cell Physiol, 2012, 53(7): 12321246.
\[15\]刘梦梦, 桑贤春, 凌英华, 等. 水稻黄绿叶基因YGL4的遗传分析和分子定位. 作物学报, 2009， 35(8): 14051409.
\[16\]Jung KH, Hur J, Ryu C H, et al., Characterization of a rice chlorophylldeficient mutant using the TDNA genetrap system. Plant Cell Physiol, 2003, 44(5): 463472.
\[17\]孙小秋, 王兵, 肖云华, 等. 水稻ygl98黄绿叶突变基因的精细定位与遗传分析. 作物学报, 2011， 37(6)： 991997.
\[18\]Zhang H T， Li J J, Yoo J H, et al. Rice chlorina1 and chlorina9 encode ChlD and ChlI subunits of Mgchelatase, a key enzyme for chlorophyll synthesis and chloroplast development. Plant Mol Biol, 2006, 62(3): 325337.
\[19\]Wang P, Gao J, Wan C, et al. Divinyl chlorophyll(ide) a can be converted to monovinyl chlorophyll(ide) a by a divinyl reductase in rice. Plant Physiol, 2010, 153(3): 9941003.
\[20\]Wu Z M, Zhang X， He B, et al. A chlorophylldeficient rice mutant with impaired chlorophyllide esterification in chlorophyll biosynthesis. Plant Physiol, 2007, 145(1): 2940.
\[21\]余新桥, 罗利军, 梅捍卫, 等. 水稻标记不育系标1A的选育与利用. 西南农业学报, 2000, 13(4): 69.
\[22\]曹立勇, 钱前, 朱旭东, 等. 紫叶标记籼型光温敏核不育系中紫S的选育及其配组的杂种优势. 作物学报, 1999, 25(1):44
