Bacterial leaf streak 1 encoding a mitogen‐activated protein kinase confers resistance to bacterial leaf streak in rice

Abstract

Summary Bacterial leaf streak (BLS) is a major bacterial disease of rice. Utilization of host genetic resistance has become one of the most important strategies for controlling BLS. However, only a few resistance genes have been characterized. Previously, a recessive BLS resistance gene bls1 was roughly mapped on chromosome 6. Here, we further delineated bls1 to a 21 kb region spanning four genes. Genetic analysis confirmed that the gene encoding a mitogen‐activated protein kinase (OsMAPK6) is the target of the allelic genes BLS1 and bls1. Overexpression of BLS1 weakened resistance to the specific Xanthomonas oryzae pv. oryzicola (Xoc) strain JZ‐8, while low expression of bls1 increased resistance. However, both overexpression of BLS1 and low expression of bls1 could increase no‐race‐specific broad‐spectrum resistance. These results indicate that BLS1 and bls1 negatively regulate race‐specific resistance to Xoc strain JZ‐8 but positively and negatively control broad‐spectrum resistance, respectively. Subcellular localization demonstrated that OsMAPK6 was localized in the nucleus. RGA4, which is known to mediate resistance to Xoc, is the potential target of OsMAPK6. Overexpression of BLS1 and low expression of bls1 showed increase in salicylic acid and induced expression of defense‐related genes, simultaneously increasing broad‐spectrum resistance. Moreover, low expression of bls1 showed increase an in jasmonic acid and abscisic acid, in company with an increase in resistance to Xoc strain JZ‐8. Collectively, our study provides new insights into the understanding of BLS resistance and facilitates the development of rice host‐resistant cultivars.

Transcriptomic and Metabolomic Approaches Deepen Our Knowledge of Plant–Endophyte Interactions

“…To confer a broad-spectrum and a durable resistance in this cereal plant, currently, the best way forward is to select among the inherent resistance genes of rice to breed disease-resistant cultivars. In this respect, many discoveries have been made recently, such as the RNase P protein subunit Rpp30 with tRNA processing (Li W. et al, 2021), executor R proteins' (Xa7 and Xa23 with EBE Avrxa23 ) response to T3Es of pathogens Wei et al, 2021), and Bacterial Leaf Streak 1 (Ma Z. et al, 2021) which encodes a protein that acts against different pathogenic strains (Chen F. et al, 2021). As another economically important crop, wheat is susceptible to Fusarium head blight (Fhb) that is caused by several Fusarium strains.…”

Comparative transcriptomic profiling of the two-stage response of rice to Xanthomonas oryzae pv. oryzicola interaction with two different pathogenic strains

“…To understand the functions of the common DEGs, we annotated these genes (Table S3 ), which included genes encoding transcription factors (MYB, WRKY, ERF, and EREBP), protein kinase-related proteins (WAKs and SAPKs) and antibody protein-related genes (disease resistance, cytochrome P450, regulation of response to stimulus, LRRs, and natural resistance-associated macrophage protein) [ 21 ]. In addition, we identified five genes closely related to BLS resistance based on previous reports [ 12 , 25 , 29 – 31 ], including OsPGIP1 ( LOC_Os05g01380 ), the phytosulfokine receptor gene Os PSKR1 ( LOC_Os02g41890 ), the resistance gene OsBLS1 ( LOC_Os06g06090 ), the bHLH transcription activator regulator gene OsbHLH6 ( LOC_Os04g23550 ), and the sulfate transporter gene OsSULTR3;6 ( LOC_Os01g52130 ). We also performed Gene Ontology (GO) analysis for these common DEGs.…”

Transcriptome Analysis in Response to Infection of Xanthomonas oryzae pv. oryzicola Strains with Different Pathogenicity

“…BLS has contributed to significant yield losses over the last decade [14], but currently there is little reported about major gene resistance to BLS pathogenesis [21]. A Guangxi common wild rice material DY19, which contains BLS-resistant gene bls2, shows high resistance to BLS [28].…”

“…Both overexpression of BLS1 and low expression of bls1 could increase salicylic acid and induce the expression of defense-related genes, simultaneously increasing the non-race specific, broad-spectrum resistance. Moreover, low expression of bls1 showed increase in JA and ABA (abscisic acid), in company with an increase the race specific resistance to the Xoc strain JZ-8 [21]. It can be seen that the defense system of rice against Xoc infection is complex, and the research on the molecular mechanism of rice resistance to BLS is at the initial stage, which needs to be further explored.…”