水稻叶片早衰突变体wss1的性状鉴定及基因定位

Identification and Molecular Mapping of Water-soaked Spot Leaf Early Senescence Mutant wss1 in Rice

叶片早衰直接降低作物产量,了解控制作物早衰的分子机制对实现作物的高产稳产具有重要的意义。本研究利用EMS诱变水稻品种金刚30,获得稳定遗传的叶片早衰突变体wss1,其在分蘖盛期叶片开始出现水浸状斑点,并发展至孕穗期叶片出现坏死症状。与野生型相比,突变体wss1株高降低30%、结实率降低22%、穗粒数减少50%。生理分析发现wss1产生水浸状斑点后,叶片叶绿素含量显著低于野生型。台盼蓝细胞组织化学染色显示,wss1叶片细胞膜系统被破坏。在wss1叶片中衰老标志基因明显上调表达,对水稻白叶枯病菌PXO99A的抗性显著减弱。wss1表型受1对隐性基因控制,该基因被定位在水稻第11染色体长臂着丝粒区附近1200 kb范围内,为进一步克隆Oswss1基因及深入研究其功能奠定了基础。

Leaf early senescence can directly reduce photosynthesis and crop yield.Unlocking the mechanism of leaf early senescence becomes important via building up the strategy to achieve high and stable rice yield.A water-soaked spot mutant(termed wss1)was identified in the population derived from EMStreated seeds of the indica rice variety JG30.At the tillering stage,the leaves of wss1 showed premature senescence,including the appearance of water-soaked spots,which further developed to the leaf necrosis.In relative to the parental line JG30,wss1 mutant showed 30%,22%and 50%reduction on the plant height,seed setting rate and number of grains per panicle,respectively.The chlorophyll content in the water-soaked spot leaves of wss1 was significantly lower than that of the wild-type plants.By trypan blue cell histochemical staining,the cell membrane of wss1 on leaves was destroyed.Genetic analysis showed that wss1 was controlled by a recessive gene(wss1),which was mapped in a 1200 kb region between markers Ch11-33 and Ch11-123.Thus,these results will benefit future molecular cloning and functional characterization of the underlying gene of Oswss1.