Gene pyramiding enhances durable blast disease resistance in rice.

Scientific reports (2015-01-15)
Shuichi Fukuoka, Norikuni Saka, Yuko Mizukami, Hironori Koga, Utako Yamanouchi, Yosuke Yoshioka, Nagao Hayashi, Kaworu Ebana, Ritsuko Mizobuchi, Masahiro Yano
ABSTRACT

Effective control of blast, a devastating fungal disease of rice, would increase and stabilize worldwide food production. Resistance mediated by quantitative trait loci (QTLs), which usually have smaller individual effects than R-genes but confer broad-spectrum or non-race-specific resistance, is a promising alternative to less durable race-specific resistance for crop improvement, yet evidence that validates the impact of QTL combinations (pyramids) on the durability of plant disease resistance has been lacking. Here, we developed near-isogenic experimental lines representing all possible combinations of four QTL alleles from a durably resistant cultivar. These lines enabled us to evaluate the QTLs singly and in combination in a homogeneous genetic background. We present evidence that pyramiding QTL alleles, each controlling a different response to M. oryzae, confers strong, non-race-specific, environmentally stable resistance to blast disease. Our results suggest that this robust defence system provides durable resistance, thus avoiding an evolutionary "arms race" between a crop and its pathogen.

MATERIALS
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