Cloning and functional analysis of an endo-PG-encoding geneRrspg1ofRhizoctonia solani, the causal agent of rice sheath blight

Abstract

By assembling the sequences of the cDNA obtained from RT-PCR, 5 -RACE and 3 -RACE, a full-length sequence of the endo-polygalacturonase (endo-PG) -encoding gene, Rrspg1, from the rice sheath blight fungus Rhizoctonia solani, was obtained. The alignment of cDNA and genomic DNA sequences indicated that there were three introns in the sequence of Rrspg1. Differences in six nucleotides and four amino acids were found between isolates originating from rice and maize. To verify the function of Rrspg1, the RNAi vector pSilent-PG-2 was constructed and used to transform the rice wild-type (WT) isolate GD-118 of R. solani. Assays of PG activity between transformants and isolate GD-118 showed that 10 transformants had significantly lower PG activity compared with WT isolate. Pathogenicity tests indicated that the virulence of six transformants was weaker than that of WT isolate, which verified that Rrspg1 plays an important role in the pathogenesis of R. solani to rice plants.Résumé: En assemblant les séquences d'ADNc obtenues par RT-PCR, 5 -RACE et 3 -RACE, une séquence complète du gène encodant Rrspg1 de l'endopolygalacturonase (endo-PG) du champignon du flétrissement de la gaine, Rhizoctonia solani, a été obtenue. L'alignement des séquences d'ADNc et d'ADNg indique qu'il y avait trois introns dans la séquence de Rrspg1. Des différences relatives à six nucléotides et à quatre acides aminés ont été décelées dans des isolats de riz et de maïs. Afin de vérifier le rôle de Rrspg1, le vecteur ARNi pSilent-PG2 a été construit et utilisé pour transformer l'isolat GD-118 de R. solani du type sauvage (WT) du riz. Des biotests sur l'activité caractérisant les transformants et l'isolat GD-118 ont montré que 10 transformants affichaient une activité PG significativement moindre que l'isolat WT. Des tests de pathogénicité ont indiqué que la virulence de six transformants était plus faible que celle de l'isolat WT, ce qui a permis de vérifier que Rrspg1 joue un rôle important dans la pathogénie de R. solani chez le riz.

Cell-wall-degrading enzymes produced in vitro and in vivo byRhizoctonia solani, the causative fungus of peanut sheath blight

“…Polygalacturonase is a principal enzyme of many fungal pathogens of plants. Previous studies have determined the important role of the PGs by molecular methods ( Shieh et al, 1997 ; Di Pietro & Roncero, 1998 ; Oeser et al, 2002 ; Yang et al, 2012a ; Chen et al, 2014 , 2017a , 2017b ). Extensive studies have been carried out into the types of PG isozymes in vivo and in vitro.…”

“…Cell-wall-degrading enzymes have been extensively studied by gene disruption, in replacement experiments and as recombinant proteins. Several PG genes have been obtained from plant fungal pathogens and it was determined that most PG genes play an important role in pathogenicity ( Shieh et al, 1997 ; Di Pietro & Roncero, 1998 ; Oeser et al, 2002 ; Yang et al, 2012a ; Chen et al, 2014 , 2017a , 2017b ). Cx gene fragments were amplified from F. oxysporum ( Sheppard et al, 1994 ).…”

Survival of Rhizoctonia solani AG‐1 IA, the Causal Agent of Rice Sheath Blight, under Different Environmental Conditions

“…The high virulent isolate GD‐118 of R. solani AG‐1 IA used in this study was isolated from the diseased rice sheath with typical symptom of sheath blight collected from Guangdong province, China, and stored at our laboratory at South China Agricultural University (Zhou and Yang ; Yang et al. ,b, 2012b).…”

Functional validation of pathogenicity genes in rice sheath blight pathogen Rhizoctonia solani by a novel host‐induced gene silencing system

“…The virulent R. solani AG-1 IA strain GD-118 (Yang et al, 2012) was grown on PDA at 28 °C in the dark for a few days. The mycelia were N. benthamiana seeds were sown on soil in pots covered with plastic films to increase humidity.…”