Parvez Saba, Asif Maryam, Ahmad Alizay, Javaid Iqra, Rasheed Muhammad Zaman, Iftikhar Romana, Aljarba Nada H, Zafar Rabia, Sarwar Aqsa, Khan Rao Sohail Ahmed, Serfraz Saad
Evolutionary Biology Lab, CABB, University of Agriculture, Faisalabad, Pakistan.
Department of Biology, College of Science, Princess Nourah Bint Abdulrahman University, Riyadh, 11671, Saudi Arabia.
BMC Plant Biol. 2025 Feb 26;25(1):259. doi: 10.1186/s12870-025-06233-2.
The Oleaceae family, encompassing key genera such as Fraxinus (ash trees), Olea (olives), Jasminum (jasmine), Syringa (lilac), and Forsythia, plays a crucial ecological and economic role. Despite their importance, the evolutionary dynamics and immune system adaptations of their NLR (Nucleotide binding leucine-rich repeats) gene family remain largely unexplored. This study employs high-throughput comparative genomics to investigate NLR gene evolution across the Oleaceae family. The genus Fraxinus is widely distributed across both the New and Old Worlds, with 23 distinct species analyzed in this study. Our results reveal a predominant strategy of gene conservation in the evolution of the NLR gene family across these species. Geographical adaptation has played a significant role, particularly in Old World ash tree species, which exhibit dynamic patterns of gene expansion and contraction within the last 50 million years. Notably, genes acquired from an ancient whole genome duplication event (~ 35 Mya) have been retained across Fraxinus lineages. In contrast, the genus Olea (olives) has undergone extensive gene expansion driven by recent duplications and significant birth of novel NLR gene families. These differences in NLR gene evolution likely enhance Olea's ability to recognize diverse pathogens through recent expansions, while Fraxinus maintains specialized immune responses through conserved genes, with potential trade-offs in pathogen adaptation and energy efficiency. In terms of NLR distribution, all species of the Oleaceae family show an enhanced pseudogenization of TIR-NLRs and expansion in CCG10-NLR. However, the comparative RNA-seq expression analysis in olive suggests that partial NLR genes, despite their incomplete structure, have significant expression and may play important roles in plant immune responses. This study provides a comprehensive analysis of NLR gene evolution within the Oleaceae family, offering insights into the adaptive mechanisms of immune response evolution across diverse genera.
木犀科包含白蜡树属（白蜡树）、油橄榄属（橄榄）、茉莉属（茉莉）、丁香属（丁香）和连翘属等关键属，具有至关重要的生态和经济作用。尽管它们很重要，但其NLR（核苷酸结合富含亮氨酸重复序列）基因家族的进化动态和免疫系统适应性在很大程度上仍未得到探索。本研究采用高通量比较基因组学来研究木犀科NLR基因的进化。白蜡树属广泛分布于新旧世界，本研究分析了23个不同的物种。我们的结果揭示了这些物种NLR基因家族进化中基因保守的主要策略。地理适应性发挥了重要作用，特别是在旧世界的白蜡树物种中，它们在过去5000万年中表现出基因扩张和收缩的动态模式。值得注意的是，从古代全基因组复制事件（约3500万年前）获得的基因在白蜡树谱系中得以保留。相比之下，油橄榄属（橄榄）由于近期的复制和新的NLR基因家族的大量产生而经历了广泛的基因扩张。NLR基因进化的这些差异可能增强了油橄榄属通过近期扩张识别多种病原体的能力，而白蜡树属则通过保守基因维持专门的免疫反应，在病原体适应性和能量效率方面可能存在权衡。在NLR分布方面，木犀科的所有物种都表现出TIR-NLRs假基因化增强和CCG10-NLR扩张。然而，橄榄的比较RNA-seq表达分析表明，部分NLR基因尽管结构不完整，但具有显著表达，可能在植物免疫反应中发挥重要作用。本研究对白蜡树科内NLR基因进化进行了全面分析，为不同属间免疫反应进化的适应性机制提供了见解。
