Thomas Treesa, Sakure Amar A, Kumar Sushil, Mishra Ankita, Ahmad Suhail, Rojasara Yogesh M, Vaja Mahesh B, Patel Dipak A
Department of Agricultural Biotechnology, Anand Agricultural University, Anand, 388110, India.
Bidi Tobacco Research Station, Anand Agricultural University, Anand, 388110, India.
Plant Cell Rep. 2025 Apr 12;44(5):96. doi: 10.1007/s00299-025-03484-z.
Root-knot nematodes threaten tomato cultivation worldwide. This study confirms Mi- 1 gene's role in defence by inducing programmed cell death, lignin accumulation, and cellular remodelling in resistant plants. Root-knot nematodes, particularly Meloidogyne species, pose a significant economic threat to tomato cultivation globally. Despite the identification of various Mi genes, their mechanisms of action are not fully understood. This study aimed to elucidate the role of the Mi- 1 gene by analysing transcriptomic data from both resistant and susceptible tomato genotypes and by constitutively expressing Mi- 1 in a susceptible cultivar. Transcriptome analysis of leaf and root samples upon RKN infection showed that the Mi- 1 gene was exclusively present in the roots of resistant plants. Further to investigate its function Mi- 1 was constitutively expressed under the CaMV 35S promoter in a susceptible tomato cultivar. Structural analysis confirmed that the Mi- 1 protein primarily localized in the cytoplasm and lacked a transmembrane motif. Following transformation, a comparative gene expression of wild-type and transformed tomato plants with genes obtained from transcriptome, revealing significant up-regulation of cellular, plant defence, and programmed cell death (PCD) related genes in the transgenic lines. Notably, the roots of the transformed plants exhibited thickened root morphology and high lignin accumulation, correlating with the expression of lignin biosynthesis genes. These findings suggested that the Mi- 1 gene is not only involved in PCD but also activates various defence-related and cellular remodelling genes by depositing the lignin in the root cell to combat against nematode attack.
根结线虫威胁着全球的番茄种植。本研究证实了Mi-1基因在抗性植物中通过诱导程序性细胞死亡、木质素积累和细胞重塑来发挥防御作用。根结线虫，尤其是根结线虫属的线虫，对全球番茄种植构成了重大经济威胁。尽管已鉴定出多种Mi基因，但其作用机制尚未完全明确。本研究旨在通过分析抗性和感病番茄基因型的转录组数据，并在感病品种中组成型表达Mi-1基因，来阐明Mi-1基因的作用。对受根结线虫感染的叶片和根样本进行转录组分析表明，Mi-1基因仅存在于抗性植物的根中。为进一步研究其功能，在感病番茄品种中，通过CaMV 35S启动子组成型表达Mi-1基因。结构分析证实，Mi-1蛋白主要定位于细胞质中，且缺乏跨膜基序。转化后，对野生型和转化番茄植株与转录组获得的基因进行比较基因表达分析，结果显示转基因系中与细胞、植物防御和程序性细胞死亡（PCD）相关的基因显著上调。值得注意的是，转化植株的根表现出根形态变粗和木质素积累增加，这与木质素生物合成基因的表达相关。这些发现表明，Mi-1基因不仅参与程序性细胞死亡，还通过在根细胞中沉积木质素来激活各种防御相关和细胞重塑基因，以对抗线虫攻击。
