Ranade Sonali Sachin, García-Gil María Rosario
Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden.
Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 901 87, Umeå, Sweden.
Planta. 2021 Jan 28;253(2):53. doi: 10.1007/s00425-020-03517-9.
Transcriptomic and exome capture analysis reveal an adaptive cline for shade tolerance in Norway spruce. Genes involved in the lignin pathway and immunity seem to play a potential role in contributing towards local adaptation to light. The study of natural variation is an efficient method to elucidate how plants adapt to local climatic conditions, a key process for the evolution of a species. Norway spruce is a shade-tolerant conifer in which the requirement of far-red light for growth increases latitudinally northwards. The objective of the study is to characterize the genetic control of local adaptation to light enriched in far-red in Norway spruce, motivated by a latitudinal gradient for the Red:Far-red (R:FR) ratio to which Norway spruce has been proven to be genetically adapted. We have established the genomic signatures of local adaptation by conducting transcriptomic (total RNA-sequencing) and genomic analyses (exome capture), for the identification of genes differentially regulated along the cline. RNA-sequencing revealed 274 differentially expressed genes in response to SHADE (low R:FR light), between the southern and northern natural populations in Sweden. Exome capture included analysis of a uniquely large data set (1654 trees) that revealed missense variations in coding regions of nine differentially expressed candidate genes, which followed a latitudinal cline in allele and genotype frequencies. These genes included five transcription factors involved in vital processes like bud-set/bud-flush, lignin pathway, and cold acclimation and other genes that take part in cell-wall remodeling, secondary cell-wall thickening, response to starvation, and immunity. Based on these results, we suggest that the northern populations might not only be able to adjust their growing season in response to low R:FR light, but they may also be better adapted towards disease resistance by up-regulation of the lignin pathway that is linked to immunity. This forms a concrete basis for local adaptation to light quality in Norway spruce, one of the most economically important conifer tree species in Sweden.
转录组学和外显子捕获分析揭示了挪威云杉耐荫性的适应性渐变群。参与木质素途径和免疫的基因似乎在促进对光照的局部适应中发挥潜在作用。自然变异研究是阐明植物如何适应当地气候条件的有效方法，这是物种进化的关键过程。挪威云杉是一种耐荫针叶树，其生长对远红光的需求随纬度向北增加。本研究的目的是描述挪威云杉对富含远红光的光照的局部适应的遗传控制，这是由挪威云杉已被证明在遗传上适应的红：远红（R：FR）比值的纬度梯度所驱动的。我们通过进行转录组学（全RNA测序）和基因组分析（外显子捕获）建立了局部适应的基因组特征，以鉴定沿渐变群差异调节的基因。RNA测序揭示了瑞典南部和北部自然种群之间响应荫蔽（低R：FR光）的274个差异表达基因。外显子捕获包括对一个独特的大数据集（1654棵树）进行分析，并揭示了9个差异表达候选基因编码区的错义变异，这些变异在等位基因和基因型频率上呈现纬度渐变群。这些基因包括五个参与芽形成/芽萌发、木质素途径和冷驯化等重要过程的转录因子，以及其他参与细胞壁重塑、次生细胞壁加厚、饥饿响应和免疫的基因。基于这些结果，我们认为北方种群不仅能够响应低R：FR光调整其生长季节，而且它们可能还通过上调与免疫相关的木质素途径而更适应抗病性。这为挪威云杉对光质的局部适应形成了具体基础，挪威云杉是瑞典经济上最重要的针叶树种之一。
