Molecular Identification of Blast Resistance Gene in Some Elite Rice (Oryza Sativa L.) Land Races and Varieties

Abstract

Background: The greatest challenge facing rice productivity in rice producing regions of the World is the occurrence of blast diseases cause by Piricularia Oryzae. In reaction, affected plants develop disease resistance strategies one of which is the expression of resistance genes by systemic defence. Aim: To identify resistance controlling gene (piz-6) against blast disease in two conventional cultivars (faro 67 and 44) and three elite landraces (CHI, IRON and C-Price). T Study Design: The study involved laboratory experiment using PCR technique. Place and Duration of Study: Two varieties of upland rice faro 44 and faro 67 were sourced from National Cereals Research Institute, Badeggi, Niger State, Nigeria while the three landraces (C-price, CHl and IRON) were obtained from Abakiliki, Ebonyi State Nigeria bet July, 2024 to October 2024. Methodology: Genomic DNA was extracted from fresh plant tissue using the Quick-DNA™ Plant/Seed Miniprep Kit (Inqaba, US) following the manufacturer’s protocol.DNA purity and concentration were determined using NanoDrop Spectrophotometer 2000C while PCR amplification of the rice genomes was carried out using the PCR master mix, OneTaq Quick-Load 2X Master Mix (New England Biolabs, US) with specific Primer, RM8225. Results: DNA concentration ranged from 74.1 to 126.9ng/µl with a purity index (absorbance ratio) ranging from 1.73 to 1.79. The study detected blast resistance gene in one conventional variety; faro 44 and one landrace; CHI. A distribution frequency of 40% of the resistance gene was obtained in the entire varieties studied. The sequences of the two varieties revealed the presence of the allele for the resistance gene (piz-6). Conclusion: The findings of this study have revealed that both conventional and landrace rice cultivars harbour blast resistance gene. However, there need for identification of more blast resistance genes in other varieties especially in our landraces and even the weedy relatives. The exploitation and utilization of new resistance genes in addition to the monitoring of virulence genes of blast fungus will better Aid understanding of resistance in rice defense mechanisms