Divergent response associates with the differential amplitudes of immunity against Magnaporthe oryzae by different blast resistance genes

Beenish Hassan ¹ Sadam Hussain Bhutto ¹ Xiao-Xiao Yin ¹ Xiu-Lian Yan ¹ Rong Liao ¹ Mao-Lin Guo ¹ Ya-Ping Tang ¹ Dai-Ming Guo ² Si-Jia Yang ¹ Faiza Gulzar ¹ Yan Li ¹ Xian-Yin Zeng ³ Zhi-Xue Zhao ¹ Wen-Ming Wang ^1*

• ¹ State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, Sichuan Province, China
• ² Rice Research Institute, Sichuan Agricultural University, Chengdu, Sichuan Province, China
• ³ Department of Bioengineering and Applied Biology, College of Life Science, Sichuan Agricultural University, Ya an, Sichuan Province, China

Rice blast disease, caused by Magnaporthe oryzae, poses the most devastating threat to global rice production. The products of most blast resistance (R) genes specifically recognize corresponding avirulence effectors from the pathogen, thereby mediating robust immune responses that are crucial for disease resistance. However, it is unclear why different R genes endow with differential amplitudes of immunity against M. oryzae. Here, we demonstrated that different blast R genes confer differential amplitudes of immunity against M. oryzae, presumably due to divergent reprogramming of transcriptional responses. We detected that three rice restorer lines exhibited differential amplitudes of immune responses, despite all lines displaying resistance to M. oryzae. To gain a deeper understanding of the immune-related genes involved, we conducted comprehensive RNA-seq analysis and RT-qPCR profiling across diverse rice lines carrying different R genes alongside the universal susceptible control line LTH. Our data indicate that different accessions carrying different R genes exhibited remarkable differentially expressed genes (DEGs), with LTH displaying the highest DEG count. Comparative analysis revealed varying degrees of overlap among DEGs across different accessions. By integrating RNA-seq and RT-qPCR data, we recommended some marker genes that distinguish the differential amplitude of immunity against M. oryzae mediated by different blast R genes. Thus, our study provides critical insights into the specific and overlapping roles of R gene-mediated immunity and proposes marker genes for conveniently assessing the amplitude of immune responses to M. oryzae.