Overexpression of a NAC transcription factor delays leaf senescence and increases grain nitrogen concentration in wheat

A - Papers appearing in refereed journals

Zhao, D., Derkx, A. P., Liu, D-C., Buchner, P. H. and Hawkesford, M. J. 2015. Overexpression of a NAC transcription factor delays leaf senescence and increases grain nitrogen concentration in wheat. Plant Biology. 17 (4), pp. 904-913.

AuthorsZhao, D., Derkx, A. P., Liu, D-C., Buchner, P. H. and Hawkesford, M. J.
Abstract

Increasing the duration of leaf photosynthesis during grain filling using slow-senescing functional stay-green phenotypes is a possible route for increasing grain yields in wheat (Triticum aestivum L.). However, delayed senescence may negatively affect nutrient remobilisation and hence reduce grain protein concentrations and grain quality. A novel NAC1-type transcription factor (hereafter TaNAC-S) was identified in wheat, with gene expression located primarily in leaf/sheath tissues, which decreased during post-anthesis leaf senescence. Expression of TaNAC-S in the second leaf correlated with delayed senescence in two doubled-haploid lines of an AvalonxCadenza population (lines 112 and 181), which were distinct for leaf senescence. Transgenic wheat plants overexpressing TaNAC-S resulted in delayed leaf senescence (stay-green phenotype). Grain yield, aboveground biomass, harvest index and total grain N content were unaffected, but NAC over-expressing lines had higher grain N concentrations at similar grain yields compared to non-transgenic controls. These results indicate that TaNAC-S is a negative regulator of leaf senescence, and that delayed leaf senescence may lead not only to increased grain yields but also to increased grain protein concentrations.

KeywordsPlant Sciences
Year of Publication2015
JournalPlant Biology
Journal citation17 (4), pp. 904-913
Digital Object Identifier (DOI)doi:10.1111/plb.12296
PubMed ID25545326
Open accessPublished as ‘gold’ (paid) open access
FunderLawes Agricultural Trust (LAT)
Chinese Scholarship Council
Biotechnology and Biological Sciences Research Council
Funder project or codeWheat
ISSN14358603
PublisherWiley

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