Wheat, Sorghum, and Forage Research Unit, USDA-ARS, Lincoln, Nebraska, United states of America.
Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, Nebraska, United states of America.
PLoS One. 2019 Sep 12;14(9):e0222080. doi: 10.1371/journal.pone.0222080. eCollection 2019.
The genetics and responses to biotic stressors of tetraploid switchgrass (Panicum virgatum L.) lowland cultivar 'Kanlow' and upland cultivar Summer are distinct and can be exploited for trait improvement. In general, there is a paucity of data on the basal differences in transcription across tissue developmental times for switchgrass cultivars. Here, the changes in basal and temporal expression of genes related to leaf functions were evaluated for greenhouse grown 'Kanlow', and 'Summer' plants. Three biological replicates of the 4th leaf pooled from 15 plants per replicate were harvested at regular intervals beginning from leaf emergence through senescence. Increases and decreases in leaf chlorophyll and N content were similar for both cultivars. Likewise, multidimensional scaling (MDS) analysis indicated both cultivar-independent and cultivar-specific gene expression. Cultivar-independent genes and gene-networks included those associated with leaf function, such as growth/senescence, carbon/nitrogen assimilation, photosynthesis, chlorophyll biosynthesis, and chlorophyll degradation. However, many genes encoding nucleotide-binding leucine rich repeat (NB-LRRs) proteins and wall-bound kinases associated with detecting and responding to environmental signals were differentially expressed. Several of these belonged to unique cultivar-specific gene co-expression networks. Analysis of genomic resequencing data provided several examples of NB-LRRs genes that were not expressed and/or apparently absent in the genomes of Summer plants. It is plausible that cultivar (ecotype)-specific genes and gene-networks could be one of the drivers for the documented differences in responses to leaf-borne pathogens between these two cultivars. Incorporating broad resistance to plant pathogens in elite switchgrass germplasm could improve sustainability of biomass production under low-input conditions.
四倍体柳枝稷（Panicum virgatum L.）低地品种“Kanlow”和高地品种 Summer 的遗传学和对生物胁迫的反应明显不同，可以用于性状改良。一般来说，柳枝稷品种在组织发育过程中基础转录差异的数据很少。在这里，我们评估了温室中生长的“Kanlow”和“Summer”植株中与叶片功能相关的基因的基础和时间表达变化。从叶片出现到衰老，每隔一段时间从 15 株植物的第 4 片叶中收集 3 个生物学重复的叶片进行混合。两个品种的叶片叶绿素和氮含量都有增加和减少。同样，多维尺度分析（MDS）分析表明，基因表达既不受品种影响，也不受品种特异性影响。不受品种影响的基因和基因网络包括与叶片功能相关的基因，如生长/衰老、碳/氮同化、光合作用、叶绿素生物合成和叶绿素降解。然而，许多编码核苷酸结合富含亮氨酸重复（NB-LRR）蛋白和与检测和响应环境信号相关的细胞壁结合激酶的基因表达存在差异。其中一些属于独特的品种特异性基因共表达网络。基因组重测序数据分析提供了几个例子，即 NB-LRRs 基因在 Summer 植株的基因组中不表达和/或明显缺失。很可能品种（生态型）特异性基因和基因网络是这两个品种对叶病原有不同反应的驱动因素之一。在优良柳枝稷种质中引入广谱植物病原体抗性可以提高低投入条件下生物量生产的可持续性。
