ORIGINAL RESEARCH article

Front. Plant Sci.

Sec. Plant Breeding

Volume 16 - 2025 | doi: 10.3389/fpls.2025.1639365

Large-scale genomic deletion in spl39 activates immune responses and confers resistance to rice bacterial blight

Provisionally accepted
Cheng  FangCheng Fang1Wei  MaWei Ma2Xiaotong  ZhuXiaotong Zhu3Lingling  PengLingling Peng3Liangzhi  TaoLiangzhi Tao1Zhiqiang  ZhaoZhiqiang Zhao4Fengbin  WangFengbin Wang4Ye  YafengYe Yafeng1Bojun  MaBojun Ma3Wu  YuejinWu Yuejin1Jie  YuanJie Yuan4*Binmei  LiuBinmei Liu1*Xifeng  ChenXifeng Chen3*Weimin  ChengWeimin Cheng1*
  • 1Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China, Hefei, China
  • 2Huaihe River Basin Eco-Environmental Monitoring and Scientific Research Center of Huaihe River Basin Ecological Environmental Supervision and Administration Bureau, Bengbu, China
  • 3Zhejiang Normal University, Jinhua, China
  • 4Institute of Crop Sciences, Xinjiang Academy of Agricultural Sciences, Urumqi, Urumqi, China

The final, formatted version of the article will be published soon.

Lesion mimic mutants (LMMs) are invaluable for uncovering the molecular mechanisms of programmed cell death (PCD) and plant immunity and identifying more LMMs expands our understanding of these complex processes.In this study, we characterized a novel rice LMM, spl39, identified through heavy-ion beam irradiation. The spl39 mutant exhibits reddish-brown lesions from the tillering stage, reduced plant height, grain size, and fertility. Chloroplast ultrastructure analysis revealed thylakoid disruption and membrane damage, contributing to reduced photosynthetic capacity. Excessive ROS accumulation and reduced antioxidative enzyme activities triggered PCD. Genetic mapping identified a 306-kb deletion in spl39, encompassing 33 genes, including 12 from the diterpenoid biosynthesis gene cluster. Transcriptomic analysis revealed upregulation of hormone signaling and defense-related pathways, consistent with elevated levels of SA, JA, auxins, and cytokinins. The spl39 mutant exhibited enhanced resistance to bacterial blight with reduced lesion lengths and increased expression of defense-related genes. These findings highlight the role of large genomic deletions in reprogramming plant metabolism and immunity, providing new insights into the mechanisms underlying lesion mimic phenotypes and disease resistance in rice.

Keywords: rice, spl39, Lesion-mimic mutant, Reactive Oxygen Species, Genomic deletion, Disease Resistance

Received: 02 Jun 2025; Accepted: 10 Jul 2025.

Copyright: © 2025 Fang, Ma, Zhu, Peng, Tao, Zhao, Wang, Yafeng, Ma, Yuejin, Yuan, Liu, Chen and Cheng. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Jie Yuan, Institute of Crop Sciences, Xinjiang Academy of Agricultural Sciences, Urumqi, Urumqi, China
Binmei Liu, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China, Hefei, China
Xifeng Chen, Zhejiang Normal University, Jinhua, China
Weimin Cheng, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China, Hefei, China

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