AUTHOR=Wang Chen , Wang Beifang , Cao Liyong , Zhang Yingxin , Gao Yu , Cao Yongrun , Zhang Yue , Liu Qunen , Zhang Xiaohui 

TITLE=Identification and Gene Mapping of the Lesion Mimic Mutant lm8015-3

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=6

YEAR=2022

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2022.809008

DOI=10.3389/fsufs.2022.809008

ISSN=2571-581X

ABSTRACT=<p>Lesion mimic mutants (<italic>LMM</italic>s) exhibit spots on leaves without fungal infection pressure. The spots confer variable resistance to pathogens in different <italic>LMM</italic>, making them useful research materials. It is unclear how the rice immune system responds to infection with the fungal pathogen <italic>Magnaporthe oryzae</italic> (<italic>M</italic>. <italic>oryzae</italic>). Here, we identified a rice <italic>LMM, lm8015-3</italic>, which shows reduced resistance to <italic>M</italic>. <italic>oryzae</italic>. We used Quantitative Real-Time PCR (qRT-PCR) to observe the immune system response to <italic>M. oryzae</italic>–induced <italic>lm8015-3</italic>. <italic>Lm8015-3</italic>, obtained from an ethyl methane sulfonate (EMS)–induced Zhonghui8015 (ZH8015) library, showed orange-yellow spots starting in the seedling stage and accumulated more H<sub>2</sub>O<sub>2</sub>, resulting in severe degradation of the chloroplast. With map-based cloning, the target gene was located on chromosome 12. Once inoculated with <italic>M. oryzae</italic>, the expression level of pathogen-related genes of <italic>lm8015-3</italic> was downregulated between 48 and 72 h. In addition, more germinating spores appeared in <italic>lm8015-3</italic>. Therefore, we conclude that <italic>M. oryzae</italic> weakening the immune system of <italic>lm8015-3</italic> from 48 to 72 h makes <italic>lm8015-3</italic> more susceptible to <italic>M. oryzae</italic>. These results suggested that understanding how <italic>LMM</italic>s defend against <italic>M. oryzae</italic> infection will contribute to improving rice breeding.</p>