控制水稻叶形基因CLF1的图位克隆

Map-based Cloning of a Curly Leaf Gene CLF1 in Rice

分蘖、株高、植株形态是水稻理想株型的3个主要农艺性状。目前对水稻理想株型的分子调控机制认识还非常有限。而叶片形态建成是决定植株形态特征的主要因子,鉴定控制水稻叶片形态建成的关键基因至关重要。本研究通过筛选水稻突变体库,获得一份光合效率显著提高的突变体(curly leaf 1,clf1),其形态学特征表现为叶片适度卷曲,经石蜡细胞学切片发现,突变体clf1近轴面的泡状细胞明显增多是导致叶片卷曲和光合效率提高的主要原因。利用图位克隆,将CLF1基因缩小在2个分子标记In Del51与In Del57之间,该区间包含44个基因。通过生物信息学分析,确定了LOC_OS02G45250为CLF1的候选基因。对LOC_OS02G45250基因进行测序,在clf1突变体中,LOC_OS02G45250基因的第六外显子缺失20 bp,造成编码产物提前终止。该基因与已报道的水稻卷叶基因Roc5(Rice outermost cell-specific gene5)为等位基因,Roc5编码产物为一个具有GL2类同源异型结构域的转录因子,不同于已报道的突变体oul1(对应于Roc5基因),突变体clf1农艺性状表现优良,具有较大的生产应用潜力。

Leaf is one of the most important photosynthetic organs and plays an important part in the productivity. We screened the riceleaf morphological variation mutants and isolated a curly leaf mutant（clf1）showing abaxial leaf rolling. The more bulliform cells numberson leaf adaxial sides in clf1 mutnat were the main reason leading to leaves curling. Using Map-Based cloning methods,the site controllingCLF1 gene was mapped in chromosome2,tightly linking with two polymorphic markers（In Del51 and In Del57）. There were 44 genes in thisregion and we predicted LOC_OS02G45250 as the target gene by bioinformatics. We found that there were 20 bp deletion in the sixth exon ofLOC_OS02G45250 and the nucleotide deletion created a premature stop codon in the predicted coding region. The clf1 was another allele ofthe reported rice curly leaf gene Roc5（Rice outermost cell-specific gene5）,whose encoded transcription factor including GL2 homologousstructure domain. Different from the oul1 mutant（loss-of-function in Roc5）,the clf1 was valuable for the production because of a betteragricultural characters.