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

Abstract

Bacterial leaf streak (BLS) caused by Xanthomonas oryzae pv. oryzicola (Xoc) is one of the most important quarantine diseases in the world. Breeding disease-resistant varieties can solve the problem of prevention and treatment of BLS from the source. The discovery of the molecular mechanism of resistance is an important driving force for breeding resistant varieties. In this study, a BLS-resistant near isogenic line NIL-bls2 was used as the material. Guangxi Xoc strain gx01 (abbreviated as WT) and its mutant strain (abbreviated as MT) with a knockout type III effectors (T3Es) gene were used to infect rice material NIL-bls2. The molecular interaction mechanism of rice resist near isogenic lines in response to infection by different pathogenic strains was analyzed by transcriptome sequencing. The results showed that there were 415, 134 and 150 differentially expressed genes (DEGs) between the WT group and the MT group at 12, 24 and 48 h of post inoculation (hpi). Through GO and KEGG enrichment analysis, it was found that, compared with non-pathogenic strains, the T3Es secreted by pathogenic strains inhibited the signal transduction pathway mediated by ethylene (ET), jasmonic acid (JA) and salicylic acid (SA), and the MAPKK (MAPK kinase) and MAPKKK (MAPK kinase kinase) in the MAPK (mitogen-activated protein kinase) cascade reaction, which prevented plants from sensing extracellular stimuli in time and starting the intracellular immune defense mechanism; and inhibited the synthesis of lignin and diterpenoid phytochemicals to prevent plants from establishing their own physical barriers to resist the invasion of pathogenic bacteria. The inhibitory effect was the strongest at 12 h, and gradually weakened at 24 h and 48 h. To cope with the invasion of pathogenic bacteria, rice NIL-bls2 material can promote wound healing by promoting the synthesis of traumatic acid at 12 h; at 24 h, hydrogen peroxide was degraded by dioxygenase, which reduced and eliminated the attack of reactive oxygen species on plant membrane lipids; and at 48 h, rice NIL-bls2 material can resist the invasion of pathogenic bacteria by promoting the synthesis of lignin, disease-resistant proteins, monoterpene antibacterial substances, indole alkaloids and other substances. Through transcriptome sequencing analysis, the molecular interaction mechanism of rice resistance near isogenic lines in response to infection by different pathogenic strains was expounded, and 5 genes, Os01g0719300, Os02g0513100, Os03g0122300, Os04g0301500, and Os10g0575100 closely related to BLS, were screened. Our work provides new data resources and a theoretical basis for exploring the infection mechanism of Xoc strain gx01 and the resistance mechanism of resistance gene bls2.

Phenylpropane biosynthesis and alkaloid metabolism pathways involved in resistance of Amorphophallus spp. against soft rot disease

“…Our results are in keeping with earlier findings implicating phenylpropanoid and indole alkaloids in the resistance response of rice ( Oryza sativa ) to Xanthomonas oryzae pv. oryzicola ( Tang et al., 2022 ), Pueraria lobata to Synchytrium puerariae Miy ( Huang et al., 2022 ), and Musa acuminata to Fusarium wilt ( Fusarium oxysporum f. sp. cubense ) ( Sun et al., 2019 ).…”

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 ).…”

“…This finding is consistent with the findings obtained for maize- R. solani interactions [ 23 ]. Furthermore, in a comparative transcriptional analysis of bls2 -mediated resistance to compatible Xoc strain (WT) and incompatible type III effectors deficiency Xoc strain (MT) interactions, there are 415 DEGs between WT and MT were identified at 12 hpi, while only 150 DEGs were found at 48 hpi [ 21 ]. Overall, PTI at 12 hpi seems to mediate a more complex signaling pathway than ETS at 3 dpi.…”

“…Identification of DR genes via transcriptomic profiling of the rice variety Hongyou-4 via inoculation with compatible and incompatible Xoc strains revealed 8 DEGs, including those encoding transcription factors (TFs), R gene analogs and the S gene of OsSWEET13 [ 20 ]. Tang et al reported the mining of five DR genes via the inoculation of a rice near-isogenic line of NLS- bls2 after inoculation with a wild-type Xoc strain and a TALE-knockout Xoc strain, which conferred compatible and incompatible interactions, respectively, on rice [ 21 ]. Meng et al identified potential disease resistance genes by comparing the transcriptomes of powdery mildew-resistant and powdery mildew-susceptible cucumber materials [ 22 ].…”