Analysis of Stored mRNA Degradation in Acceleratedly Aged Seeds of Wheat and Canola in Comparison to Arabidopsis

Abstract

Seed aging has become a topic of renewed interest but its mechanism remains poorly understood. Our recent analysis of stored mRNA degradation in aged Arabidopsis seeds found that the stored mRNA degradation rates (estimated as the frequency of breakdown per nucleotide per day or β value) were constant over aging time under stable conditions. However, little is known about the generality of this finding to other plant species. We expanded the analysis to aged seeds of wheat (Triticum aestivum) and canola (Brassica napus). It was found that wheat and canola seeds required much longer periods than Arabidopsis seeds to lose seed germination ability completely under the same aging conditions. As what had been observed for Arabidopsis, stored mRNA degradation (∆Ct value in qPCR) in wheat and canola seeds correlated linearly and tightly with seed aging time or mRNA fragment size, while the quality of total RNA showed little change during seed aging. The generated β values reflecting the rate of stored mRNA degradation in wheat or canola seeds were similar for different stored mRNAs assayed and constant over seed aging time. The overall β values for aged seeds of wheat and canola showed non-significant differences from that of Arabidopsis when aged under the same conditions. These results are significant, allowing for better understanding of controlled seed aging for different species at the molecular level and for exploring the potential of stored mRNAs as seed aging biomarkers.

Exploring Breakthroughs in Three Traits Belonging to Seed Life

“…Interestingly, the data from [125] also indicate that the majority of Arabidopsis seed-stored mRNA have a similar and constant rate of degradation (i.e., the time for the mRNA level to decrease by 50% is constant) during seed aging. These findings were ratified in canola and wheat, two valuable agricultural species [126]. This and previous work indicate that the damage or degradation of stored mRNA occurred randomly along the length of this RNA, and also propose that stored mRNA degradation during seed aging is a general phenomenon for seeds [124,125].…”

“…Recently, observed fragmentation of seed-stored mRNAs in soybean embryonic axis by transcriptomic analysis, and suggested that mRNA breakage occurs at random positions [124]. Later, Zhao et al (2020) elegantly showed in Arabidopsis that the degradation of seedstored mRNA is greatly correlated with seed-aging time. Stored mRNA of almost all the ubiquitination-related and heat-shock protein (HSP) genes analyzed decreased gradually in aged seeds.…”

Nitric oxide–an antidote to seed aging modifies meta-tyrosine content and expression of aging-linked genes in apple embryos

“…The asymptomatic phase of seed aging (corresponding probably to 7 days of apple seeds aging) is hard to determine if based only on seed germination tests ( Zhao et al, 2020a , b ). It has been proposed that stored mRNA (the amount and quality) may serve as an indicator of the progression of seed aging ( Zhao et al, 2020a , b ). The authors using Arabidopsis seeds indicated that stored mRNA degraded at a constant rate over the aging time.…”

Research Article Evaluation of DNA integrity as a potential marker to detect aging in soybean (<i>Glycine</i> <i>max</i>) seeds

“…In our study, the potential of qPCR to estimate DNA degradation level in aged seed samples was evaluated only based on C t value differences among samples that were aged for different periods (0, 6, 12, 24, 48, 72 or 96 h). Recently, C t s value were used to evaluate mRNA integrity in naturally and artificially aged Arabidopsis (Zhao et al, 2020b), canola (Brassica napus) and wheat (T. aestivum) (Zhao et al, 2020a) seeds using qPCR. Both authors evaluated different DNA sequences using a pair of primers for amplification of a long fragment (1,000 to 2,000 bp) and another for amplification of a short fragment (~250bp).…”

“…Despite their wide use, they do not allow to clearly detect the distinct stages of aging of the conserved seeds, indicating only the final stages of this process, that is, when there is a lack of uniformity and delay in the germination process, loss of seedling vigor, formation of abnormal seedlings and seed death. The time under conservation is also an indicator of seed aging status, but it is known that seeds age at different speeds also depending on the different conditions to which they are given, such as post-harvest treatments or in sample preparation for conservation in the long-term (Zhao et al, 2020a). Low viability or nongermination makes the use of germplasm unfeasible when necessary and can lead to the loss of alleles or gene combinations involved in the expression of characteristics of great current or potential value for agriculture (Faleiro, 2013).…”