Transgenic rice expressing Trichoderma spp. endochitinase gene exhibits moderate resistance to sheath blight

Rice is a staple food consumed by almost half of the world's population. The crop is prone to a myriad of diseases, and sheath blight caused by Rhizoctonia solani poses a major risk to its cultivation, due to non-availability of resistant genes in the crop germplasm. As a consequence, most of the cultivars are susceptible to the disease incurring significant crop yield losses. This study delineates development of transgenic rice expressing Trichoderma spp. endochitinase through Agrobacterium-mediated genetic transformation. The presence of transgene in T-0 plants was detected by PCR, and its transcription confirmed through RT-PCR. The transgenic plants revealed up to six-fold higher relative transgene expression as compared to non-transgenic plant through qRT-PCR. Upon bioassay with virulent R. solani isolate, T-0, T-1 and homozygous T-2 progeny plants (possessing high level of endochitinase expression) exhibited moderately resistant reaction to the pathogen. The quantitative analysis for sheath blight incidence displayed significantly lower AUDPC values in T-1 progeny plants as compared to NT plant, with former displaying up to 67.65% reduction in disease index coupled with slower disease progression. The moderate resistant reaction was verified in T-2 progeny plants, thus confirming the role of endochitinase in improved resistance. These plants are a valuable source for introgression of sheath blight resistance in rice breeding programs.

Automated summary

This study developed transgenic rice expressing Trichoderma spp. endochitinase gene through Agrobacterium-mediated genetic transformation, resulting in moderately resistant reaction to sheath blight caused by Rhizoctonia solani. These transgenic plants can be a valuable source for improving sheath blight resistance in rice breeding programs.