Genetic analysis and identification of SSR markers associated with rice blast disease in a BC₂F₁ backcross population

Abstract

ABSTRACT. Rice (Oryza sativa L.) blast disease is one of the most destructive rice diseases in the world. The fungal pathogen, Magnaporthe oryzae, is the causal agent of rice blast disease. Development of 2 N. Hasan et al. Genetics and Molecular Research 16 (1): gmr16019280 resistant cultivars is the most preferred method to achieve sustainable rice production. However, the effectiveness of resistant cultivars is hindered by the genetic plasticity of the pathogen genome. Therefore, information on genetic resistance and virulence stability are vital to increase our understanding of the molecular basis of blast disease resistance. The present study set out to elucidate the resistance pattern and identify potential simple sequence repeat markers linked with rice blast disease. A backcross population (BC 2 F 1 ), derived from crossing MR264 and Pongsu Seribu 2 (PS2), was developed using marker-assisted backcross breeding. Twelve microsatellite markers carrying the blast resistance gene clearly demonstrated a polymorphic pattern between both parental lines. Among these, two markers, RM206 and RM5961, located on chromosome 11 exhibited the expected 1:1 testcross ratio in the BC 2 F 1 population. The 195 BC 2 F 1 plants inoculated against M. oryzae pathotype P7.2 showed a significantly different distribution in the backcrossed generation and followed Mendelian segregation based on a single-gene model. This indicates that blast resistance in PS2 is governed by a single dominant gene, which is linked to RM206 and RM5961 on chromosome 11. The findings presented in this study could be useful for future blast resistance studies in rice breeding programs.

Genetic analysis of the resistance to rice blast in the BC2F1population derived from MR263 × Pongsu Seribu 1

“…An isolate of M. oryzae cannot be avirulent to the rice plant, unless the rice plant has genes that make it resistant to that isolate [24,36]. Partial resistance can be race specific [1,2,18]. The findings of this research support the research output reported by IRRI, Philippines; that is, that one or two dominant genes are present and the 'Mashuri' cultivar was susceptible (S).…”

“…MR263, a popular and high-yielding rice variety, was used as a recurrent parent with elite agronomic traits that is susceptible to blast. The BC 2 F 1 population was produced from a cross between MR263 and PS1 and genotyped with suitable SSR markers that were linked to blast resistance genes [2,5].…”

“…Currently, the severity of plant diseases and pests is increasing due to climate change. Blast, one of the most important diseases of rice, is caused by Magnaporthe oryzae; it has been recognized as the most important and devastating fungal disease worldwide [1,2]. Blast is responsible for yield losses as high as 50% throughout the world [2,3].…”

“…Blast, one of the most important diseases of rice, is caused by Magnaporthe oryzae; it has been recognized as the most important and devastating fungal disease worldwide [1,2]. Blast is responsible for yield losses as high as 50% throughout the world [2,3]. Although blast disease can be managed by fungicides, the inherent quality of disease resistance can be useful for appropriate breeding programmes [4,5].…”

“…Adhikari et al [22] suggested that the use of a disease resistant variety offers an inexpensive and environmentally friendly approach for crop protection. Pongsu Seribu 1 (PS1), a local Malaysian variety with lower yield, has been used as a source of broad-spectrum blast resistance genes and as a donor parent in a marker-assisted backcrossing programme, whereas MR263 is a high-yielding variety (>6 t/ha) with fewer days to maturity (97-104 days) but blast susceptible [2,5]. The objective of this study was to select suitable simple sequence repeat (SSR) markers linked to the rice blast resistance gene (Pi) in the BC 2 F 1 population derived from a cross between the resistant variety PS 1 and the susceptible rice cultivar MR263.…”