An analysis of dormancy, ABA responsiveness, after-ripening and pre-harvest sprouting in hexaploid wheat (Triticum aestivum L.) caryopses

Abstract

Embryo and caryopsis dormancy, abscisic acid (ABA) responsiveness, after-ripening (AR), and the disorder pre-harvest sprouting (PHS) were investigated in six genetically related wheat varieties previously characterized as resistant, intermediate, or susceptible to PHS. Timing of caryopsis AR differed between varieties; AR occurred before harvest ripeness in the most PHS-susceptible, whereas AR was slowest in the most PHS-resistant. Whole caryopses of all varieties showed little ABA-responsiveness during AR; PHS-susceptible varieties were responsive at the beginning of the AR period whereas PHS-resistant showed some responsiveness throughout. Isolated embryos showed relatively little dormancy during grain-filling and most varieties exhibited a window of decreased ABA-responsiveness around the period of maximum dry matter accumulation (physiological maturity). Susceptibility to PHS was assessed by overhead misting of either isolated ears or whole plants during AR; varieties were clearly distinguished using both methods. These analyses allowed an investigation of the interactions between the different components of seed development, compartments, and environment for the six varieties. There was no direct relationship between speed of caryopsis AR and embryo dormancy or ABA-responsiveness during seed maturation. However, the velocity of AR of a variety was closely associated with the degree of susceptibility to PHS during AR suggesting that these characters are developmentally linked. Investigation of genetic components of AR may therefore aid breeding approaches to reduce susceptibility to PHS.

Expression of the aldehyde oxidase 3, ent-copalyl diphosphate synthase, and VIVIPAROUS 1 genes in wheat cultivars differing in their susceptibility to pre-harvest sprouting

“…In the literature, there are some reports characterizing differences between PHS-susceptible and PHS-resistant genotypes of wheat (Walker-Simmons, 1987;Corbineau et al, 2000;Gerjets et al, 2010;De Laethauwer et al, 2012). In this study, we analyzed expression of two genes involved in the biosynthesis of ABA and GAs (AAO3 and CPS3, respectively), and one gene (VP1) for a transcription factor of ABA-regulated genes.…”

“…The final step of ABA biosynthesis is oxidation of abscisic aldehyde to ABA by aldehyde oxidase, the enzyme encoded by the AAO3 gene (Seo et al, 2000). The experiments performed by González-Guzmán et al (2004) and Seo et al (2004) showed that among four aldehyde oxidase genes in Arabidopsis, AAO3 played a major role in ABA biosynthesis in seeds. The biosynthetic pathway of gibberellins also has been thoroughly studied in Arabidopsis.…”

Approaches to improve wheat grain quality: breeding for falling number

“…Прямой отбор на УкПП в полевых условиях крайне затруднителен даже в дождливые сезоны из-за влияния на этот признак, во-первых, различий между сортами/лини-ями и между колосьями одного растения по фенологии, во-вторых, взаимодействия между генотипом и средой (Biddulph et al, 2007;Gerjets et al, 2010;�e Pauw еt al., 2012;��kić et al, 2012). Более эффективна оценка сортов и линий в искусственных условиях.…”

Importance of cytomatrix-bound polysomes to synthesis of lysine-containing proteins in triticale germs under ABA treatment

“…Along with other regulators of plant growth and development, ABA plays a major role in the control of embryo maturation and seed formation via regulation of storage reserve deposition, acquisition of desiccation tolerance as well as induction of primary dormancy and suppression of precocious germination (Still et al 1994;Bartels et al 1988;Gerjets et al 2010). Although more research dealing with mechanisms of ABA action has been conducted, many questions remain unanswered.…”