A trehalose-6-phosphate phosphatase enhances anaerobic germination tolerance in rice

Abstract

Global socioeconomic developments create strong incentives for farmers to shift from transplanted to direct-seeded rice (DSR) as a means of intensification and economization(1). Rice production must increase to ensure food security(2) and the bulk of this increase will have to be achieved through intensification of cultivation, because expansion of cultivated areas is reaching sustainable limits(3). Anaerobic germination tolerance, which enables uniform germination and seedling establishment under submergence(4), is a key trait for the development of tropical DSR varieties(5,6). Here, we identify a trehalose-6-phosphate phosphatase gene, OsTPP7, as the genetic determinant in qAG-9-2, a major quantitative trait locus (QTL) for anaerobic germination tolerance(7). OsTPP7 is involved in trehalose-6-phosphate (T6P) metabolism, central to an energy sensor that determines anabolism or catabolism depending on local sucrose availability(8,9). OsTPP7 activity may increase sink strength in proliferating heterotrophic tissues by indicating low sugar availability through increased T6P turnover, thus enhancing starch mobilization to drive growth kinetics of the germinating embryo and elongating coleoptile, which consequently enhances anaerobic germination tolerance.

Transitioning to the Next Phase: The Role of Sugar Signaling throughout the Plant Life Cycle

“…A rice (Oryza sativa) TPP gene (TPP7) was identified as QTL for anaerobic germination tolerance (Kretzschmar et al, 2015). Presence of a functional TPP results in a lower T6P/Suc ratio and increased amylase-dependent starch mobilization for coleoptile growth.…”

A Tale of Two Sugars: Trehalose 6-Phosphate and Sucrose

“…Recently, a quantitative trait locus for anaerobic germination tolerance in rice (Oryza sativa) was found to be linked to expression of a functional OsTPP7 gene in the tolerant genotype, Khao Hlan On (KHO); the OsTPP7 gene is essentially missing from the intolerant IR64 genotype (Kretzschmar et al, 2015). Metabolites were measured in embryos and coleoptiles from a transgenic IR64 line expressing the KHO-OsTPP7 gene and a near-isogenic line containing the KHO-OsTPP7 locus introgressed into the IR64 background.…”

Development of High-Yielding Rice Varieties Suitable for Swampy Lands in Indonesia

“…Likewise, quantitative traits loci and genes for tolerance to various abiotic stresses, including drought, salinity, submergence during vegetative stage, submergence during germination, stagnant flooding and iron toxicity have been identified and used in molecular breeding programs Thomson et al 2010;Iftekharuddaula et al 2011;Septiningsih et al 2012;Septiningsih et al 2013b;Baltazar et al 2014;Dixit et al 2014;Kretzschmar et al 2015;Toledo et al 2015;Gonzaga et al 2016;Iftekharuddaula et al 2016a;Singh et al 2016). In addition, elite breeding lines tolerant to multiple abiotic stresses have been developed through conventional breeding (Gregorio et al 2002;Kumar et al 2008;Collard et al 2013a;Collard et al 2013b).…”