Genetic network involving antagonistic pair of bHLH genes that regulate grain size/weight of rice

2014 Fiscal Year Final Research Report

• Project/Area Number: 24658001
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Breeding science
• Research Institution: Chiba University
• Principal Investigator: SASSA Hidenori 千葉大学, 園芸学研究科, 准教授 (50295507)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: イネ / 粒長 / bHLH転写因子

Outline of Final Research Achievements

Grain size is a major yield component in rice, and partly controlled by the sizes of the lemma and palea. We have previously shown that an antagonistic pair of basic helix-loop-helix (bHLH) proteins is involved in determining rice grain length by controlling cell length in the lemma/palea. Overexpression of an atypical bHLH, named POSITIVE REGULATOR OF GRAIN LENGTH 1 (PGL1), in lemma/palea increased grain length and weight in transgenic rice. PGL1 is an atypical non-DNA-binding bHLH and found to function as an inhibitor of a typical DNA-binding bHLH which was named ANTAGONIST OF PGL1 (APG). In this study, we produced transgenic rice plants overexpressing PGL1 under the control of ubiquitin promoter. The transgenic plants showing prolonged grains exhibited reduced seed fertility. Similar phenotype has been reported for a brassinosteroid signaling bHLH gene BU1, suggesting the functional relationships between PGL1 and BU1.

Free Research Field

植物遺伝育種学