Involvement of homocastasterone, salicylic and abscisic acids in the regulation of drought and freezing tolerance in doubled haploid lines of winter barley

Abstract

Ten doubled haploid (DH) lines of winter barley with an increased range of freezing/drought tolerance were used to identify phytohormones involved in plant stress acclimation. Cold hardening and drought stress were applied at the most critical stages of plant development on young seedlings and heading plants, respectively. The level of the phytohormones was significantly higher at heading, more than 5-fold in respect of salicylic acid (SA) and total brassinosteroids (BRs) and 1.7-fold in the case of abscisic acid (ABA). Moreover, the spectrum of detectable BRs increased from one-homocastasterone (HCS)-found in seedlings to four BRs identified in heading plants [HCS, castasterone (CS), teasterone and dolicholide], with the last one detected for the first time in cereal species. To some extent freezing tolerance seems to be determined by native hormonal status as control seedlings of tolerant DH lines contained 1.4-and 2.3-fold lower amount of ABA and HCS and 2.3-fold higher amount of SA in comparison to freezing-sensitive ones. Such dependency was not observed in heading plants as significant variation in CS content was the only detected difference. Under stress treatments, tolerant DH lines accumulated significantly lower (75-81%) amount of ABA, which probably reflected lower stress intensity resulting from another defence strategy. In contrast, stress-induced significant almost 2-fold increase in HCS/CS and 2-3-fold decrease in SA content specific for tolerant DH lines of barley suggest the involvement of these molecules in freezing/drought defence. Detected correlations suggest their interaction with nonspecific peroxidase and low molecular weight antioxidants.

Molecular Dynamics of Chloroplast Membranes Isolated from Wild-Type Barley and a Brassinosteroid-Deficient Mutant Acclimated to Low and High Temperatures

“…Moreover, in the leaf material, only brassinolide, castasterone, and homocastasterone were found in that study, while in this study, many more BR were detected in the pure chloroplasts, including dolicholide, dolichosterone, homodolicholide, and also 28-norcastasterone and 24-epibrassinolide. Interestingly, dolicholide had already been detected by us in the barley leaves of other cultivars [ 46 ], but not in Delisa or its 522DK mutant [ 20 ]. In our opinion, the differences in the detectable BR profile in the Delisa and 522DK leaves and chloroplasts are due to the fact that in the case of the leaves, 300 mg of fresh leaf material was used for the BR extraction, while in the case of the chloroplast isolation, 40 g of the leaves (25 plants) were used to obtain 1.5 g of the chloroplasts (300 mg pure chloroplasts per sample for the BR analysis).…”

Candidate Genes for Freezing and Drought Tolerance Selected on the Basis of Proteome Analysis in Doubled Haploid Lines of Barley

“…The six DH lines of winter barley used in this study were selected from DHs produced by androgenesis initiation and they showed increased variation in freezing and drought tolerance in comparison with their parental genotypes [16]. Their thorough examination allowed the identification of several physiological and metabolic parameters associated with stress tolerance acquisition [8][9][10]. In particular, the analysis of proteome profiles provided a basis for the selection of the genes whose expression changes were analyzed in this study [8,9].…”

“…Six doubled haploid (DH) lines of winter barley examined thoroughly in previous studies with respect to parameters involved in freezing and drought tolerance [8][9][10] were used in the present study. Both of these stress factors impose a water deficit and are considered serious threats to winter barley productivity, especially when they occur at the most critical and sensitive stages, i.e., on young seedlings (freezing) and on plants at the booting stage (drought).…”

“…Both of these stress factors impose a water deficit and are considered serious threats to winter barley productivity, especially when they occur at the most critical and sensitive stages, i.e., on young seedlings (freezing) and on plants at the booting stage (drought). The studied DH lines were selected from a population of DHs produced using the anther culture technique from Polish breeding materials and showed increased variation in freezing and drought tolerance levels in comparison with their parental genotypes [8][9][10]. The selected DH lines were examined previously with respect to changes induced by water deficit in the functioning of the photosynthetic apparatus, antioxidative defense and proteome and phytohormone accumulation.…”

Proteins, Small Peptides and Other Signaling Molecules Identified as Inconspicuous but Possibly Important Players in Microspores Reprogramming Toward Embryogenesis

“…Elimination of heterozygosity simplifies genome sequencing, reverse breeding, quantitative genetic research and discovering of recessive, dominant and deleterious mutations. That's why DHs are interesting objects of studies in many research areas including physiology, molecular biology, genetics and epigenetics (Maluszynski et al, 1996;Castillo et al, 2001;Touraev et al, 2001;Forster et al, 2007;Szarejko and Forster, 2007 and references therein;Dirks et al, 2009;Dunwell, 2010;Chauhan and Khurana, 2011;Ferrie and Möllers, 2011;Krzewska et al, 2012Krzewska et al, , 2017Marathi et al, 2012;Żur et al, 2014a,b, 2015aBarakat et al, 2017;Ren et al, 2017;Song et al, 2017;Shchukina et al, 2018;Tyrka et al, 2018;Nowicka et al, 2019;Shi et al, 2019;Testillano, 2019;Wajdzik et al, 2019;Bilichak et al, 2020;Malaga et al, 2020). Furthermore, DH technology combined with marker assisted selection (MAS) enables precise identification of plants with enhanced/silenced expression of even one gene of interest within the genome.…”