State Key Laboratory for Conservation and Utilization of Agro Bioresources, Guangxi Key Laboratory for Sugarcane Biology, Guangxi University, Nanning, 530005, China.
Nuclear Institute of Agriculture (NIA), Tando Jam, 70060, Pakistan.
BMC Plant Biol. 2020 Nov 23;20(1):532. doi: 10.1186/s12870-020-02737-1.
Viruses are infectious pathogens, and plant virus epidemics can have devastating consequences to crop yield and quality. Sugarcane mosaic virus (SCMV, belonging to family Potyviridae) is one of the leading pathogens that affect the sugarcane crop every year. To combat the pathogens' attack, plants generate reactive oxygen species (ROS) as the first line of defense whose sophisticated balance is achieved through well-organized antioxidant scavenging pathways.
In this study, we investigated the changes occurring at the transcriptomic level of ROS associated and ROS detoxification pathways of SCMV resistant (B-48) and susceptible (Badila) sugarcane genotypes, using Saccharum spontaneum L. genome assembly as a reference genome. Transcriptomic data highlighted the significant upregulation of ROS producing genes such as NADH oxidase, malate dehydrogenase and flavin-binding monooxygenase, in Badila genotype after SCMV pathogenicity. To scavenge the ROS, the Badila genotype illustrated a substantial enhancement of antioxidants i.e. glutathione s-transferase (GST), as compared to its resistant counterpart. GST is supposed to be a key indicator of pathogen attacks on the plant. A remarkably lower GST expression in B-48, as compared to Badila, indicated the development of resistance in this genotype. Additionally, we characterized the critical transcription factors (TFs) involved in endowing resistance to B-48. Among these, WRKY, AP2, NAC, bZIP, and bHLH showed enhanced expression in the B-48 genotype. Our results also confirmed the linkage of transcriptomic data with the enzymatic and qPCR data. The estimation of enzymatic activities for superoxide dismutase, catalase, ascorbate peroxidase, and phenylalanine ammonia-lyase supported the transcriptomic data and evinced higher resistance in B-48 genotype.
The current study supported the efficiency of the B-48 genotype under SCMV infection. Moreover, comparative transcriptomic data has been presented to highlight the role of significant transcription factors conferring resistance to this genotype. This study provides an in-depth knowledge of the expression profiling of defense mechanisms in sugarcane.
病毒是传染性病原体，植物病毒病会对作物产量和质量造成毁灭性影响。甘蔗花叶病毒（SCMV，属于马铃薯 Y 病毒科）是每年影响甘蔗作物的主要病原体之一。为了抵御病原体的攻击，植物会产生活性氧（ROS）作为第一道防线，其复杂的平衡是通过组织良好的抗氧化剂清除途径实现的。
在这项研究中，我们使用甘蔗野生种 L.基因组组装作为参考基因组，研究了 SCMV 抗性（B-48）和敏感（Badila）甘蔗基因型中与 ROS 相关的 ROS 解毒途径的转录组水平变化。转录组数据突出显示了 ROS 产生基因的显著上调，如 NADH 氧化酶、苹果酸脱氢酶和黄素结合单加氧酶，在 SCMV 致病性后 Badila 基因型中。为了清除 ROS，Badila 基因型的抗氧化剂，如谷胱甘肽 S-转移酶（GST），相对于其抗性对应物有了显著的增强。GST 被认为是植物受到病原体攻击的关键指标。与 Badila 相比，B-48 中 GST 的表达显著降低，表明该基因型产生了抗性。此外，我们还对赋予 B-48 抗性的关键转录因子（TF）进行了特征描述。其中，WRKY、AP2、NAC、bZIP 和 bHLH 在 B-48 基因型中表达增强。我们的结果还证实了转录组数据与酶和 qPCR 数据的联系。超氧化物歧化酶、过氧化氢酶、抗坏血酸过氧化物酶和苯丙氨酸解氨酶的酶活性估计支持了转录组数据，并表明 B-48 基因型具有更高的抗性。
本研究支持了 B-48 基因型在 SCMV 感染下的效率。此外，比较转录组数据突出了赋予该基因型抗性的重要转录因子的作用。本研究为甘蔗防御机制的表达谱提供了深入的了解。
