Ojeda-Rivera Jonathan Odilón, Ulloa Mauricio, Roberts Philip A, Kottapalli Pratibha, Wang Congli, Nájera-González Héctor-Rogelio, Payton Paxton, Lopez-Arredondo Damar, Herrera-Estrella Luis
Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, United States.
USDA-ARS, PA, CSRL, Plant Stress and Germplasm Development Research, Lubbock, TX, United States.
Front Plant Sci. 2022 Apr 13;13:858313. doi: 10.3389/fpls.2022.858313. eCollection 2022.
Cotton ( spp.) is the most important renewable source of natural textile fiber and one of the most cultivated crops around the world. Plant-parasitic nematode infestations, such as the southern Root-Knot Nematode (RKN) , represent a threat to cotton production worldwide. Host-plant resistance is a highly effective strategy to manage RKN; however, the underlying molecular mechanisms of RKN-resistance remain largely unknown. In this study, we harness the differences in RKN-resistance between a susceptible (Acala SJ-2, SJ2), a moderately resistant (Upland Wild Mexico Jack Jones, WMJJ), and a resistant (Acala NemX) cotton entries, to perform genome-wide comparative analysis of the root transcriptional response to infection. RNA-seq data suggest that RKN-resistance is determined by a constitutive state of defense transcriptional behavior that prevails in the roots of the NemX cultivar. Gene ontology and protein homology analyses indicate that the root transcriptional landscape in response to RKN-infection is enriched for responses related to jasmonic and salicylic acid, two key phytohormones in plant defense responses. These responses are constitutively activated in NemX and correlate with elevated levels of these two hormones while avoiding a fitness penalty. We show that the expression of cotton genes coding for disease resistance and receptor proteins linked to RKN-resistance and perception in plants, is enhanced in the roots of RKN-resistant NemX. Members of the later gene families, located in the confidence interval of a previously identified QTL associated with RKN resistance, represent promising candidates that might facilitate introduction of RKN-resistance into valuable commercial varieties of cotton. Our study provides novel insights into the molecular mechanisms that underlie RKN resistance in cotton.
棉花（棉属物种）是天然纺织纤维最重要的可再生来源，也是全球种植最广泛的作物之一。植物寄生线虫侵染，如南方根结线虫（RKN），对全球棉花生产构成威胁。寄主植物抗性是管理根结线虫的一种高效策略；然而，抗根结线虫的潜在分子机制仍 largely 未知。在本研究中，我们利用一个感病（阿卡拉 SJ - 2，SJ2）、一个中度抗病（陆地棉野生墨西哥杰克琼斯，WMJJ）和一个抗病（阿卡拉 NemX）棉花品种在抗根结线虫方面的差异，对根部感染后的转录反应进行全基因组比较分析。RNA 测序数据表明，抗根结线虫能力由 NemX 品种根部普遍存在的防御转录行为的组成状态决定。基因本体论和蛋白质同源性分析表明，响应根结线虫感染的根部转录图谱富含与茉莉酸和水杨酸相关的反应，这两种是植物防御反应中的关键植物激素。这些反应在 NemX 中组成性激活，并与这两种激素水平升高相关，同时避免了适应性代价。我们表明，编码与植物中根结线虫抗性和感知相关的抗病和受体蛋白的棉花基因在抗根结线虫的 NemX 根部表达增强。后一个基因家族的成员位于先前鉴定的与根结线虫抗性相关的 QTL 的置信区间内，是有望将根结线虫抗性引入有价值的棉花商业品种的候选基因。我们的研究为棉花抗根结线虫的分子机制提供了新的见解。
