Ousseini I S, Bakasso Y, Kane N A, Couderc M, Zekraoui L, Mariac C, Manicacci D, Rhoné B, Barnaud A, Berthouly-Salazar C, Assoumane A, Moussa D, Moussa T, Vigouroux Y
Institut de Recherche pour le Développement, Montpellier, France.
Université Abdou Moumouni de Niamey, Niamey, Niger.
Heredity (Edinb). 2017 Aug;119(2):88-94. doi: 10.1038/hdy.2017.13. Epub 2017 Mar 15.
Phenotypic changes in plants can be observed along many environmental gradients and are determined by both environmental and genetic factors. The identification of alleles associated with phenotypic variations is a rapidly developing area of research. We studied the genetic basis of phenotypic variations in 11 populations of wild pearl millet (Pennisetum glaucum) on two North-South aridity gradients, one in Niger and one in Mali. Most of the 11 phenotypic traits assessed in a common garden experiment varied between the populations studied. Moreover, the size of the inflorescence, the number of flowers and aboveground dry mass co-varied positively with a decrease in rainfall. To decipher the genetic basis of these phenotypes, we used an association mapping strategy with a mixed model. We found two SNPs on the same myosin XI contig significantly associated with variations in the average number of flowers. Both the allele frequency of the two SNPs and the average number of flowers co-varied with the rainfall gradient on the two gradients. Interestingly, this gene was also a target of selection during domestication. The Myosin XI gene is thus a good candidate for fitness-related adaptation in wild populations.
植物的表型变化可沿许多环境梯度观察到，并且由环境和遗传因素共同决定。鉴定与表型变异相关的等位基因是一个快速发展的研究领域。我们在两条南北向干旱梯度带上研究了11个野生珍珠粟（Pennisetum glaucum）种群表型变异的遗传基础，一条在尼日尔，另一条在马里。在一个共同园圃实验中评估的11个表型性状中的大多数在研究的种群之间存在差异。此外，花序大小、花的数量和地上部干质量与降雨量的减少呈正协变。为了解析这些表型的遗传基础，我们使用了一种混合模型的关联作图策略。我们在同一条肌球蛋白XI重叠群上发现了两个单核苷酸多态性（SNP）与花的平均数量变异显著相关。这两个SNP的等位基因频率和花的平均数量在两条梯度带上均与降雨梯度协变。有趣的是，该基因也是驯化过程中的一个选择靶点。因此，肌球蛋白XI基因是野生种群中与适应性相关的适应性的一个良好候选基因。
