Dataset Information

Comparative genome analyses of four rice-infecting Rhizoctonia solani isolates reveal extensive enrichment of homogalacturonan modification genes.

ABSTRACT:

Background

Plant pathogenic isolates of Rhizoctonia solani anastomosis group 1-intraspecific group IA (AG1-IA) infect a wide range of crops causing diseases such as rice sheath blight (ShB). ShB has become a serious disease in rice production worldwide. Additional genome sequences of the rice-infecting R. solani isolates from different geographical regions will facilitate the identification of important pathogenicity-related genes in the fungus.

Results

Rice-infecting R. solani isolates B2 (USA), ADB (India), WGL (India), and YN-7 (China) were selected for whole-genome sequencing. Single-Molecule Real-Time (SMRT) and Illumina sequencing were used for de novo sequencing of the B2 genome. The genomes of the other three isolates were then sequenced with Illumina technology and assembled using the B2 genome as a reference. The four genomes ranged from 38.9 to 45.0 Mbp in size, contained 9715 to 11,505 protein-coding genes, and shared 5812 conserved orthogroups. The proportion of transposable elements (TEs) and average length of TE sequences in the B2 genome was nearly 3 times and 2 times greater, respectively, than those of ADB, WGL and YN-7. Although 818 to 888 putative secreted proteins were identified in the four isolates, only 30% of them were predicted to be small secreted proteins, which is a smaller proportion than what is usually found in the genomes of cereal necrotrophic fungi. Despite a lack of putative secondary metabolite biosynthesis gene clusters, the rice-infecting R. solani genomes were predicted to contain the most carbohydrate-active enzyme (CAZyme) genes among all 27 fungal genomes used in the comparative analysis. Specifically, extensive enrichment of pectin/homogalacturonan modification genes were found in all four rice-infecting R. solani genomes.

Conclusion

Four R. solani genomes were sequenced, annotated, and compared to other fungal genomes to identify distinctive genomic features that may contribute to the pathogenicity of rice-infecting R. solani. Our analyses provided evidence that genomic conservation of R. solani genomes among neighboring AGs was more diversified than among AG1-IA isolates and the presence of numerous predicted pectin modification genes in the rice-infecting R. solani genomes that may contribute to the wide host range and virulence of this necrotrophic fungal pathogen.

SUBMITTER: Lee DY

PROVIDER: S-EPMC8028249 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Sheath blight disease caused by Rhizoctonia solani Kuhn (teleomorph; Thanatephorus cucumeris) is a major constraint in rice production. Among the different anastomosis groups (AGs) of Rhizoctonia solani, AG1-IA causes sheath blight of rice, which induce necrotic lesions on leaf sheaths of the infected plants. Several reports contradict the host specificity of anastomosis groups in Rhizoctonia solani. There is lack of information on the pathogenicity genes of these Rhizoctonia solani anastomosis groups during sheath blight infection in rice. In the present study, Rhizoctonia solani isolates collected from diverse rice growing regions of India were screened for anastomosis groups and two groups namely, AG1-IA, AG2-2 were identified. Accordingly, comparative studies were made with AG1-IA (GenBank ID: 16,395) and AG2-2 (GenBank ID: 2,318,768) group sequences, which enabled the identification of specific gene clusters (119 in AG1-IA and 604 in AG2-2) belonging to these groups. Pathogen Host Interaction (PHI) blast with these specific gene clusters could further identify genes involved in host pathogen interaction (38 in AG1_IA and 150 in AG2-2), which were shortlisted for qRT-PCR validation based on qcov cutoff values representing different phenotypic categories of PHI blast. Expression analysis-based validation in sheath blight susceptible (Pusa Basmati 1) and resistant (Pusa 1908-13-12-5) rice genotypes showed that most of the genes expressed significantly higher in the susceptible variety Pusa Basmati 1. The genes like inorganic phosphate transporter (AG1_IPT), Bromodomain containing protein (AG1_BrD), Aldehyde dehydrogenase (AG1_AldD), AMP binding domain (AG1_AMP) and Heme peroxidase (AG1_HmPr) were upregulated in the susceptible genotype, PB 1 at 72hpi compared to Pusa 1908-13-12-5. Among these, inorganic phosphate transporter (AG1_IPT), Bromodomain containing protein (AG1_BrD) and Heme peroxidase (AG1_HmPr) were specific to Rhizoctonia solani AG1-IA. Through the present study, we could demonstrate the AG1-IA-specific interactions of Rhizoctonia solani causing sheath blight disease of rice, which is a step forward in understanding the specificity of Rhizoctonia solani with reference to sheath blight disease of rice.Supplementary informationThe online version contains supplementary material available at 10.1007/s13205-021-02934-1.

Project description:Rice is a staple food crop and is a major source of employment and income in the world. However, the attack of fungal disease poses a serious threat to the crop growth and productivity and leads toward yield loses. Therefore, current study was performed to evaluate the biocontrol potential of Lactobacillus and Weissella spp. on basmati rice against Rhizoctonia solani. Agar disc method was performed to evaluate the antifungal activity of both bacteria against R. solani. Petri plate and pot experiments were conducted to evaluate the growth promotion and biocontrol potential of both bacteria in Basmati rice under R. solani stress. Results indicated that maximum antifungal activity (82%) was recorded by Lactobacillus sp. Maximum phosphate solubilization and siderophore production was recorded by Weissella sp. In petri plate experiment, maximum root length, root fresh and dry weight (36%, 40% and 13%) was recorded by Weissella sp. and maximum shoot length and shoot fresh weight (99% and 107%) by Lactobacillus sp. In pot experiment, both bacteria enhanced the growth parameters of Basmati rice including root and shoot length, fresh and dry weight as well as no. of lateral roots. Application of Weissella sp. resulted in maximum increase (332% and 134%) in chlorophyll a and b content while Lactobacillus sp. + R. solani showed maximum (42%) carotenoid contents. Lactobacillus sp. + R. solani showed maximum increase in the proline (54%) and sugar contents (100%) while Lactobacillus sp. alone showed maximum (35%) soluble protein contents. Plant defense enzymes i-e SOD (400%), POD (25%), CAT (650%), PPO (14%) and PAL (124%) were notably increased by Weissella sp. + R. solani and Lactobacillus sp + R. solani. The Lactobacillus sp showed the best results in antifungal activity against R. solani and Weissella sp. showed the best results in production of defense enzymes in basmati rice against R. solani stress and can be suggested as the potent biocontrol agents for the rice crop.