Field priming with cytokinins enhances seed viability of wheat after low temperature storage

Abstract

Field experiments were conducted with two winter wheat cultivars that were primed with 6-benzylaminopurine (6-BA) or kinetin at the concentration 10 mg/L twice during the grain filling stage. After priming, wheat physiological parameters were measured in the field, and the analysis of yield was performed after harvest. Harvested seeds were subjected to low temperature storage for 12 months at –18 °С simulating conservation conditions in genebanks. In field experiments, treated plants exhibited up to 14% higher productivity, higher fresh and dry weight, and chlorophyll content index of flag leaves. Priming significantly improved germination, seedling vigour and growth parameters. In 5-days-old seedlings developed from low temperature stored seeds of field primed plants, the average accumulation of malondialdehyde and H<sub>2</sub>O<sub>2</sub> was estimated 25% lower, which contributed to higher cell membrane stability. These results correlated positively with growth characteristics of 15-days-old seedlings. The stimulating action of cytokinin priming was more pronounced in the modern cv. Geya-1 compared to the older cv. Sadovo 772 and could be attributed to improved anti-aging mechanism connected with better protection against oxidative damage.

Plant hormone cytokinin at the crossroads of stress priming and control of photosynthesis

“…These compounds and their volatile derivatives are well-documented as priming agents in many physiological processes (Farmer and Ryan, 1990;Engelberth et al, 2011;Song and Ryu, 2018;Avramova, 2019;Zhao et al, 2020;Singewar et al, 2021). In last decades, the participation of CKs in biotic (Choi et al, 2011;Cortleven et al, 2019) and abiotic (Barciszewski et al, 2000;Wani et al, 2016) stress responses has also been demonstrated; however, less is known about the molecular aspects of CKs in priming. Similarities in the defense mechanisms mediated by CKs and other hormones or Green Leaf Volatiles (GLVs) suggest that CKs play a more important role in the priming process than previously thought.…”

“…CKs are essential in orchestrating an immune response, most likely through the crosstalk mechanisms with other hormonal pathways. Importantly, CKs are significantly involved in plantpathogen interactions through crosstalk with the SA pathway (reviewed Choi et al, 2011). The CK transcription factor ARR2 confers resistance to Pseudomonas syringae in Arabidopsis via interaction with SA response factor TGA3 and binding to the PR1 promoter.…”

“…It has been recently reported that priming of wheat seeds with benzylaminopurine (BAP) and kinetin (KIN) applied by spraying the wheat plants during the grain filling stage resulted in up to 14% higher productivity, higher fresh and dry weight, and chlorophyll content index of flag leaves ( Chipilski et al., 2021 ). In addition to the positive impact on photosynthesis, another way in which CKs can influence plant fitness and yield is their natural ability to suppress oxidative stress, which has been also repeatedly associated with defense priming in plants ( Kerchev et al., 2020 ).…”

“…In addition to the positive impact on photosynthesis, another way in which CKs can influence plant fitness and yield is their natural ability to suppress oxidative stress, which has been also repeatedly associated with defense priming in plants ( Kerchev et al., 2020 ). The offspring of CK-treated plants during the grain filling stage showed a lower accumulation of stress markers in field conditions demonstrating the transgenerational effect of this stress imprint ( Chipilski et al., 2021 ). The CK-primed enhanced protection against oxidative damage was demonstrated on 15-day-old seedlings of wheat (cv.…”

“…Previous exposure to a mild abiotic stress including heat, cold, osmotic or water stress can also improve resistance of various environmental stresses ( Thomashow, 2010 ; Amooaghaie and Tabatabaie, 2017 ; Fan et al., 2018 ; Lemmens et al., 2019 ). Priming with plant hormones (hormopriming) is another popular and effective approach how to improve overall plant development ( Iqbal et al., 2006 ; Nawaz et al., 2013 ; Chipilski et al., 2021 ; Vedenicheva et al., 2022 ), with cytokinins (CKs) emerging as a potentially interesting new group of hormopriming regulators that have been repeatedly shown to influence several developmental processes, including photosynthesis and senescence ( Sobol et al., 2014 ; Vylíčilová et al., 2016 ; Hönig et al., 2018 ; Kučerová et al., 2020 ). In this review, we focus on possible CK effects in stress priming, with particular emphasis on the maintenance of photosynthesis, which is likely the backbone of the adaptive response mediated by this plant hormone.…”