Genetic diversity of submergence stress response in cytoplasms of the Triticum-Aegilops complex

Abstract

Genetic diversity in cytoplasmic and nuclear genomes and their interaction affecting adaptive traits is an attractive research subject in plants. We addressed submergence stress response of wheat that has become increasingly important but remained largely uninvestigated. Our primary aim was to disclose cytoplasmic diversity using nucleus-cytoplasm (NC) hybrids possessing a series of heterologous cytoplasms in a common nuclear background. Effects of submergence on seedling emergence and growth from imbibed seeds were studied and compared with euplasmic lines. Marked phenotypic variabilities were observed among both lines, demonstrating divergent cytoplasmic and nuclear effects on submergence response. NC hybrids with cytoplasm of Aegilops mutica showed a less inhibition, indicative of their positive contribution to submergence tolerance, whereas cytoplasms of Aegilops umbellulata and related species caused a greater inhibition. Superoxide dismutase (SOD) activity showed a marked increase accompanied by retardation of seedling growth in a susceptible NC hybrid. The observation suggested that the elevated SOD activity was resulted from a high level of reactive oxygen species accumulated and remained in susceptible seedlings. Taken together, our results point to the usefulness of NC hybrids in further studies needed to clarify molecular mechanisms underlying the nucleus-cytoplasm interaction regulating submergence stress response in wheat.

Differential and interactive effects of cytoplasmic substitution and seed ageing on submergence stress response in wheat (Triticum aestivum L.)

“…at the 5% level of significance [41]. Part of the data for non-aged seeds were taken from the previous report [51].…”

“…In our previous study, we demonstrated marked diversities affecting submergence stress response in both cytoplasmic and nuclear genomes in wheat using a series of NC hybrids and wheat accessions [51]. In the present study, we evaluated wheat response to submergence in combination with seed ageing.…”

High sensitivity of roots to salt stress as revealed by novel tip bioassay in wheat seedlings

“…The aims of our study were two-pronged, i.e., (1) developing a simple, efficient and reliable screening method of wheat germplasms with high and uniform ability of growth under salt stress, and (2) comparing tissue sensitivity to salt stress between shoots and roots. The bioassay method is critical for accurate phenotyping of complex traits such as abiotic environmental stress response [12]. The bioassay for precision assessment requires simplicity, repeatability and verifiability.…”

“…Twelve of these lines consisted of genetic stocks with a wide range of morphological and geographical diversity [11]. They showed large variability in their sensitivity to submergence stress [12]. The remaining seven lines included two Japanese cultivars (Norin 61 and Shiroganekomugi), two cultivars released from Green Revolution project in SIMMYT (Penjamo 62 and Siete Cerros 66) and three cultivars each from Bulgaria (Pliska), France (Soissons) and Uklaine (Mironovskaya 808).…”

Taking Advantage of Organelle Genomes in Plant Breeding: An Integrated Approach

“…In a recent work Takenaka et al (2018) studied cytoplasmic genetic diversity affecting seedling emergence and growth under submergence stress. Using a set of 37 nucleo-cytoplasmic hybrids carrying the nuclear genome of the wheat cultivar Chinese Spring and different cytoplasms of the Triticum-Aegilops complex they found a significant diversity with divergent cytoplasmic effects on submergence response.…”