一份新的水稻斑点叶突变体spl32的鉴定和基因定位

从F2(粤晶丝苗2号/H4)群体中,鉴定出一份显性斑点叶突变体spl32(spotted leaf 32)。其叶片褐色斑点受自然光诱导,在幼穗分化期从叶尖逐渐扩散至叶鞘,台盼蓝染色表明斑点并非由细胞死亡引起。以从F5杂合个体分离出的正常叶色植株为对照,斑点叶植株的穗粒数、结实率显著降低。斑点出现后,spl32的POD活性和MDA含量均显著高于对照;同时,spl32叶片光合色素含量降低,但荧光动力学参数并无显著变化。抽穗期人工接菌表明,spl32对水稻白叶枯病菌抗性较对照显著提高。遗传分析表明spl32斑点性状由一个显性基因Spl32(t)控制,利用F2(02428/spl32)群体将其定位在第11染色体Ind-c和RM206之间,推测该基因为一个新的水稻斑点叶基因。

Characterization of a Novel Spotted Leaf Mutant spl32 and Mapping of Spl32(t) Gene in Rice (Oryza sativa)

A dominant spotted-leaf mutant of rice was isolated from F₂ (Yuejingsimiao 2/H4) population. The mutant, designated as spl32 (spotted-leaf 32), initiated brown spots on leaf apex at the panicle differentiation period, and then gradually spread them to whole leaf and sheath. Trypan blue staining indicated that the formation of spots was not caused by cell death. Taken normal green leaf plants segregated from heterozygous F₅ as control (CK), we found seeds per panicle and seed setting rate of spotted leaf plants were significantly lower than these of CK. After appearance of spots, the POD activity and MDA content of spl32 were significantly higher than these of CK, while photosynthetic pigment content in spl32 was reduced, without significant changes in chlorophyll fluorescence parameters. The resistance to rice bacterial blight in spl32 was greatly improved by inoculation of Xanthomonas oryzae pv. oryzae at heading period. The spotted-leaf trait of spl32 was verified to be controlled by a dominant gene that temporarily designated as Spl32(t). The novel rice spotted-leaf gene was mapped between markers Ind-c and RM206 on chromosome 11 with a F₂ (02428/Spl32) population.