Truong Sandra K, McCormick Ryan F, Rooney William L, Mullet John E
Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas 77843 Biochemistry and Biophysics Department, Texas A&M University, College Station, Texas 77843.
Soil and Crop Sciences Department, Texas A&M University, College Station, Texas 77843.
Genetics. 2015 Nov;201(3):1229-38. doi: 10.1534/genetics.115.178608. Epub 2015 Aug 31.
The efficiency with which a plant intercepts solar radiation is determined primarily by its architecture. Understanding the genetic regulation of plant architecture and how changes in architecture affect performance can be used to improve plant productivity. Leaf inclination angle, the angle at which a leaf emerges with respect to the stem, is a feature of plant architecture that influences how a plant canopy intercepts solar radiation. Here we identify extensive genetic variation for leaf inclination angle in the crop plant Sorghum bicolor, a C4 grass species used for the production of grain, forage, and bioenergy. Multiple genetic loci that regulate leaf inclination angle were identified in recombinant inbred line populations of grain and bioenergy sorghum. Alleles of sorghum dwarf-3, a gene encoding a P-glycoprotein involved in polar auxin transport, are shown to change leaf inclination angle by up to 34° (0.59 rad). The impact of heritable variation in leaf inclination angle on light interception in sorghum canopies was assessed using functional-structural plant models and field experiments. Smaller leaf inclination angles caused solar radiation to penetrate deeper into the canopy, and the resulting redistribution of light is predicted to increase the biomass yield potential of bioenergy sorghum by at least 3%. These results show that sorghum leaf angle is a heritable trait regulated by multiple loci and that genetic variation in leaf angle can be used to modify plant architecture to improve sorghum crop performance.
植物截获太阳辐射的效率主要由其结构决定。了解植物结构的遗传调控以及结构变化如何影响性能，可用于提高植物生产力。叶片倾斜角是指叶片相对于茎干伸出的角度，是植物结构的一个特征，它影响着植物冠层截获太阳辐射的方式。在这里，我们在农作物双色高粱（一种用于生产谷物、饲料和生物能源的C4禾本科植物）中发现了叶片倾斜角存在广泛的遗传变异。在谷物和生物能源高粱的重组自交系群体中鉴定出多个调控叶片倾斜角的基因座。高粱矮化3基因（一种编码参与极性生长素运输的P糖蛋白的基因）的等位基因显示可使叶片倾斜角变化高达34°（0.59弧度）。利用功能结构植物模型和田间试验评估了叶片倾斜角的遗传变异对高粱冠层光截获的影响。较小的叶片倾斜角使太阳辐射更深地穿透冠层，预计由此产生的光重新分布可使生物能源高粱的生物量产量潜力提高至少3%。这些结果表明，高粱叶片角度是一个受多个基因座调控的可遗传性状，叶片角度的遗传变异可用于改变植物结构，以提高高粱作物的性能。
