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Expression patterns of key hormones related to Pea (Pisum sativum L.) embryo physiological maturity shift in response to accelerated growth conditions

Citation

Ribalta, FM and Pazos-Navarro, M and Edwards, K and Ross, JJ and Croser, JS and Ochatt, SJ, Expression patterns of key hormones related to Pea (Pisum sativum L.) embryo physiological maturity shift in response to accelerated growth conditions, Frontiers in Plant Science, 10 Article 1154. ISSN 1664-462X (2019) [Refereed Article]


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DOI: doi:10.3389/fpls.2019.01154

Abstract

Protocols have been proposed for rapid generation turnover of temperate legumes under conditions optimized for day-length, temperature, and light spectra. These conditions act to compress time to flowering and seed development across genotypes. In pea, we have previously demonstrated that embryos do not efficiently germinate without exogenous hormones until physiological maturity is reached at 18 days after pollination (DAP). Sugar metabolism and moisture content have been implicated in the modulation of embryo maturity. However, the role of hormones in regulating seed development is poorly described in legumes. To address this gap, we characterized hormonal profiles (IAA, chlorinated auxin [4-Cl-IAA], GA20, GA1, and abscisic acid [ABA]) of developing seeds (1022 DAP) from diverse pea genotypes grown under intensive conditions optimized for rapid generation turnover and compared them to profiles of equivalent samples from glasshouse conditions. Growing plants under intensive conditions altered the seed hormone content by advancing the auxin, gibberellins (GAs) and ABA profiles by 4 to 8 days, compared with the glasshouse control. Additionally, we observed a synchronization of the auxin profiles across genotypes. Under intensive conditions, auxin peaks were observed at 10 to 12 DAP and GA20 peaks at 10 to 16 DAP, indicative of the end of embryo morphogenesis and initiation of seed desiccation. GA1 was detected only in seeds harvested in the glasshouse. These results were associated with an acceleration of embryo physiological maturity by up to 4 days in the intensive environment. We propose auxin and GA profiles as reliable indicators of seed maturation. The biological relevance of these hormonal fluctuations to the attainment of physiological maturity, in particular the role of ABA and GA, was investigated through the study of precocious in vitro germination of seeds 12 to 22 DAP, with and without exogenous hormones. The extent of sensitivity of developing seeds to exogenous ABA was strongly genotype-dependent. Concentrations between 5 and 10 M inhibited germination of seeds 18 DAP. Germination of seeds 12 DAP was enhanced 2.5- to 3-fold with the addition of 125 M GA3. This study provides further insights into the hormonal regulation of seed development and in vitro precocious germination in legumes and contributes to the design of efficient and reproducible biotechnological tools for rapid genetic gain.

Item Details

Item Type:Refereed Article
Keywords:abscisic acid, auxins, embryo physiological maturity, generation turnover, gibberellins, hormone regulation, legumes
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Grains and seeds
Objective Field:Grain legumes
UTAS Author:Ross, JJ (Associate Professor John Ross)
ID Code:147908
Year Published:2019
Funding Support:Australian Research Council (DP130103357)
Web of Science® Times Cited:6
Deposited By:Plant Science
Deposited On:2021-11-23
Last Modified:2021-11-23
Downloads:0

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