Sheath blight (SB) caused by Rhizoctonia solani fungus is one of the
problems in rice production, but scientists have not found a source of
resistance within the rice germplasm. Thus, researchers from Southwest
University in China searched for other sources of resistance and tested a
gene from bitter melon. The findings are published in Transgenic Research.
The research team developed transgenic lines harboring the chitinase gene
(McCHIT1) of bitter melon with good SB resistance. Then they inoculated the
transgenic and wild-type rice plants with hyphae of highly pathogenic SB
strain. Results showed that there was higher SB disease incidence in
wild-type plants (92%) than in transgenic lines (37-44%). From 1 to 5 days
after inoculation with fungus hyphae, the chitinase activity in transgenic
plants with high SB resistance was 2 to 5.5 and 1.8 to 2.7x that of
wild-type and disease-susceptible transgenic plants, respectively. There was
also a strong correlation between SB resistance and chitinase activity in
transgenic rice plants.
Based on the results, the researchers concluded that McCHIT1 from bitter
melon can be used to protect rice plants from SB infection.