水稻半外卷叶突变体sol1的表型分析与基因定位

适度卷曲有利于提高水稻叶片的光合效率,增加植株光合产物的有效积累量。我们利用甲基磺酸乙酯(EMS)处理籼型水稻保持系西农1B,获得一个稳定遗传的水稻半外卷叶突变体。该突变体从十叶期开始各叶片逐渐向外卷曲直至半卷状,并伴随茎秆半矮化和叶片披垂,暂被命名为semi-outcurved leaf 1(sol1)。与野生型(WT)相比,sol1的叶片卷曲指数均达到30%以上(P<0.01);倒一、倒二、倒三、倒四节节间长度和穗长极显著缩短,倒一、倒二、倒三叶的叶夹角显著或极显著增加;有效穗数、千粒重、每穗实粒数、结实率显著或极显著下降,一次枝梗数则增加11.3%(P<0.05)。sol1的蒸腾速率、胞间CO2浓度、气孔导度显著高于野生型。石蜡切片显示,sol1倒一叶的泡状细胞体积变小,数量显著增多,表皮细胞体积略微增大。遗传分析表明,sol1的半外卷叶性状受1对隐性核基因调控,定位于6号染色体标记JY6-3和JY6-10之间165 kb的物理范围内,共含15个注释基因。qRT-PCR结果表明,与泡状细胞相关的内卷基因和外卷叶基因RL14、Roc5、REL1在突变体sol1中呈不同程度的上调,NRL、BRD1、OsHox32、ADL1、LC2则呈不同程度的下调。研究结果为SOL1基因的克隆和功能研究奠定了基础。

Phenotype characterization and gene mapping of the semi-outcurved leaf mutant sol1 in rice (Oryza sativa L.)

Moderate curling of leaves helps to improve the photosynthetic efficiency, and increase the overall effective accumulation of photosynthate. We identified a stable mutant from the library constructed by treating indica maintainer line Xinong 1B with ethyl methane sulfonate (EMS). Leaves of the mutant gradually curled outwards into a semi-coiled shape, accompanied by semi-dwarfing of the culm and leaf drooping from the 10-leaf stage, the mutant was temporarily named as semi-outcurved leaf 1 (sol1). The calculated leaf curl index of sol1 was 30%, statistically higher than that of wild type (WT, P < 0.01). Panicle length and internode length of Top 1 (the 1st leaf from top), Top 2 (the 2nd leaf from top), Top 3 (the 3rd leaf from top), and Top 4 (the 4th leaf from top) were very significantly decreased. The leaf angles of Top 1, Top 2, and Top 3 were significantly or very significantly increased. The number of effective panicles, 1000-grain weight, filled grain number per panicle, and seed setting rate of the mutant sol1 were significantly or very significantly decreased, while primary branch number increased by 11.3%, statistically higher than that of WT (P < 0.05). The transpiration rate, intercellular CO₂ concentration and stomatal conductance of sol1 were significantly higher than those of wild type. The results of paraffin section showed that the bulliform cells of the Top1 of sol1 exhibited smaller, but their number increased significantly, and the volume of epidermal cells increased slightly. Genetic analysis indicated that sol1 was controlled by a recessive nuclear gene. SOL1 was precisely located in the physical distance of 165 kb between the markers of JY6-3 and JY6-10 on the short arm of chromosome 6, with 15 annotated genes. The results of qRT-PCR showed that RL14, Roc5, and REL1 related to bulliform cells were up- regulated in mutant sol1, while NRL, BRD1, OsHox32, ADL1, LC2 down-regulated. The results of the present study provide a basis for SOL1 cloning, and functional dissection as well.