Highly Sprouting-Tolerant Wheat Grain Exhibits Extreme Dormancy and Cold Imbibition-Resistant Accumulation of Abscisic Acid

• DOI: 10.1093/pcp/pcw051
• Publication Date: 2016-03-13T01:47:56Z
• Authors: Yu-ichi Kashiwakura; Daisuke Kobayashi; Yusuke Jikumaru; Yumiko Takebayashi; Eiji Nambara; Mitsunori Seo; Yuji Kamiya; Tetsuo Kushiro; Naoto Kawakami
• Keywords: Sprouting; Imbibition; Wheat grain

Pre-harvest sprouting (PHS) of wheat ( Triticum aestivum L.) grains induces hydrolyzing enzymes such as α-amylase, which considerably decreases product quality. PHS occurs when cool and wet weather conditions before harvest break dormancy induce grain germination. In this study, we used PHS-tolerant varieties, Gifu-komugi (Gifu) OS38, to characterize the mechanisms both breakage maintenance at low temperatures. Physiologically mature Gifu exhibited after imbibition 20°C, but germinated 15°C. contrast, OS38 remained dormant even temperatures 5°C. Embryo half-grains cut out from by similar conventional varieties worldwide. However, embryo were still dormant. Hormonome pharmacological analyses suggested that ABA gibberellin metabolism are important for temperature-dependent breakage. Imbibition 15°C decreased levels increased in embryos freshly harvested grains. Additionally, induced expression catabolism genes, TaABA8 ′ OH1 OH2 , biosynthesis gene, TaGA3ox2 embryos. grains, while suppressed these embryos, TaNCED TaGA3ox2. These results show regulatory mechanism influencing genes may be critical Our findings should help improve PHS-resistant breeding programs.