title: NAL1 allele from a rice landrace greatly increases yield in modern indica cultivars.
abstract: Increasing crop production is essential for securing the future food supply in developing countries in Asia and Africa as economies and populations grow. However, although the Green Revolution led to increased grain production in the 1960s, no major advances have been made in increasing yield potential in rice since then. In this study, we identified a gene, SPIKELET NUMBER (SPIKE), from a tropical japonica rice landrace that enhances the grain productivity of indica cultivars through pleiotropic effects on plant architecture. Map-based cloning revealed that SPIKE was identical to NARROW LEAF1 (NAL1), which has been reported to control vein pattern in leaf. Phenotypic analyses of a near-isogenic line of a popular indica cultivar, IR64, and overexpressor lines revealed increases in spikelet number, leaf size, root system, and the number of vascular bundles, indicating the enhancement of source size and translocation capacity as well as sink size. The near-isogenic line achieved 13-36% yield increase without any negative effect on grain appearance. Expression analysis revealed that the gene was expressed in all cell types: panicles, leaves, roots, and culms supporting the pleiotropic effects on plant architecture. Furthermore, SPIKE increased grain yield by 18% in the recently released indica cultivar IRRI146, and increased spikelet number in the genetic background of other popular indica cultivars. The use of SPIKE in rice breeding could contribute to food security in indica-growing regions such as South and Southeast Asia.
authors.affiliation: Plant Breeding, Genetics, and Biotechnology, International Rice Research Institute, Metro Manila, Philippines.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Fujita
authors.forename: Kurniawan Rudi
authors.initials: KR
authors.lastname: Trijatmiko
authors.forename: Analiza Grubanzo
authors.initials: AG
authors.lastname: Tagle
authors.forename: Maria Veronica
authors.initials: MV
authors.lastname: Sapasap
authors.forename: Yohei
authors.initials: Y
authors.lastname: Koide
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Sasaki
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Tsakirpaloglou
authors.forename: Ritchel Bueno
authors.initials: RB
authors.lastname: Gannaban
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishimura
authors.forename: Seiji
authors.initials: S
authors.lastname: Yanagihara
authors.forename: Yoshimichi
authors.initials: Y
authors.lastname: Fukuta
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Koshiba
authors.forename: Inez Hortense
authors.initials: IH
authors.lastname: Slamet-Loedin
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ishimaru
authors.forename: Nobuya
authors.initials: N
authors.lastname: Kobayashi
mesh_terms: D000483:Alleles; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D009928:Organ Specificity / Q000502:physiology; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins
keywords: gene validation; marker-assisted breeding; pleiotropy; qTSN4