Enhanced resistance to rice blast and sheath blight in rice ( oryza sativa L.) by expressing the oxalate decarboxylase protein Bacisubin from Bacillus subtilis

Karmakar

Plant Biotechnology Journal

et al. 2020

179

163

Summary Rice sheath blight disease, caused by the basidiomycetous necrotroph Rhizoctonia solani, became one of the major threats to the rice cultivation worldwide, especially after the adoption of high‐yielding varieties. The pathogen is challenging to manage because of its extensively broad host range and high genetic variability and also due to the inability to find any satisfactory level of natural resistance from the available rice germplasm. It is high time to find remedies to combat the pathogen for reducing rice yield losses and subsequently to minimize the threat to global food security. The development of genetic resistance is one of the alternative means to avoid the use of hazardous chemical fungicides. This review mainly focuses on the effort of better understanding the host–pathogen relationship, finding the gene loci/markers imparting resistance response and modifying the host genome through transgenic development. The latest development and trend in the R. solani–rice pathosystem research with gap analysis are provided.

Section: Genes Which Act Against Pathogen Effectormentioning

confidence: 99%

Understanding sheath blight resistance in rice: the road behind and the road ahead

Karmakar

Plant Biotechnology Journal

et al. 2020

179

163

“…The highly virulent isolates of R. solani have been identified to produce more OA than weakly virulent isolates (Nagarajkumara et al 2005). During R. solani infection, OA inhibits the synthesis of various phenolic substances and acts synergistically with polygalacturonases (PGs) to cause pH instability and cell wall degradation (Liang et al 2018;Qi et al 2017;Rollins and Dickman, 2001). Besides, OA triggers programmed cell death in host plants, and thus promoting infection (Cessna et al 2000;Heller et al 2013;Kabbage et al 2013).…”

Section: Secondary Metabolitesmentioning

confidence: 99%

“…To combat OA action, host plants have evolved to effectively decompose oxalate by synthesizing and secreting oxalate oxidases (Karmakar et al 2015;Molla et al 2013). Bacteria and fungi are also able to produce oxalate decarboxylases (ODCs) to inhibit OA accumulation (Liang et al 2015;Qi et al 2017). During R. solani colonization of host plants, several ODC genes were significantly up-regulated (Ghosh et al 2019;Liang et al 2015).…”

Section: Other Signal Moleculesmentioning

confidence: 99%

Strategies to Manage Rice Sheath Blight: Lessons from Interactions between Rice and Rhizoctonia solani

Wei

et al. 2021

Rice

Rhizoctonia solani is an important phytopathogenic fungus with a wide host range and worldwide distribution. The anastomosis group AG1 IA of R. solani has been identified as the predominant causal agent of rice sheath blight, one of the most devastating diseases of crop plants. As a necrotrophic pathogen, R. solani exhibits many characteristics different from biotrophic and hemi-biotrophic pathogens during co-evolutionary interaction with host plants. Various types of secondary metabolites, carbohydrate-active enzymes, secreted proteins and effectors have been revealed to be essential pathogenicity factors in R. solani. Meanwhile, reactive oxygen species, phytohormone signaling, transcription factors and many other defense-associated genes have been identified to contribute to sheath blight resistance in rice. Here, we summarize the recent advances in studies on molecular interactions between rice and R. solani. Based on knowledge of rice-R. solani interactions and sheath blight resistance QTLs, multiple effective strategies have been developed to generate rice cultivars with enhanced sheath blight resistance.

“…Bacillus species can indirectly inhibit phytopathogens through biocontrol strategies including the repossession of pathogenic iron by siderophores, the production of hydrolytic enzymes to degrade pathogenic cell walls, and the production of antibiotics to interfere with pathogenic respiration (Ahmad et al, 2017;Li et al, 2014;Li et al, 2017;Qi et al, 2017;Zhang and Sun, 2018). Huang et al (2020) isolated B. cereus HS24 from a rice farm; B. cereus HS24 could significantly reduce conidium germination by interfering with the M. oryzae Ca 2+ signaling pathway.…”

Section: Strainsmentioning

confidence: 99%

Screening and Application of Bacillus Strains Isolated from Nonrhizospheric Rice Soil for the Biocontrol of Rice Blast

2020

Rice blast, caused by Magnaporthe oryzae, is one of the most destructive rice diseases worldwide. The aim of this study was to screen bacterial isolates to efficiently prevent the occurrence of rice blast. A total of 232 bacterial isolates were extracted from nonrhizospheric rice soil and were screened for antifungal activity against M. oryzae using a leaf segment assay. Strains S170 and S9 showed significant antagonistic activity against M. oryzae in vitro and in leaf disk assays, and controlled M. oryzae infection under greenhouse conditions. The results showed that strains S170 and S9 could effectively control rice leaf blast and panicle neck blast after five spray treatments in field. This suggested that the bacterial strains S170 and S9 were valuable and promising for the biocontrol of rice disease caused by M. oryzae. Based on 16S rDNA, and gyrA and gyrB gene sequence analyses, S170 and S9 were identified as Bacillus amyloliquefaciens and B. pumilus, respectively. The research also demonstrated that B. amyloliquefaciens S170 and B. pumilus S9 could colonize rice plants to prevent pathogenic infection and evidently suppressed plant disease caused by 11 other plant pathogenic fungi. This is the first study to demonstrate that B. amyloliquefaciens and B. pumilus isolated from nonrhizospheric rice soil are capable of recolonizing internal rice stem tissues.