Mapping of additive and epistatic QTLs linked to seed longevity in bread wheat (Triticum aestivum L.)

Plant genetic resources are stored and regenerated in > 1750 gene banks storing > 7,000,000 accessions. Since seeds are the primary storage units, research on seed longevity is of particular importance. Quantitative trait loci (QTL) analysis of 15 traits related to seed longevity and dormancy using 7584 high-quality SNPs recorded across 2 years and originated from five production years revealed a total of 46 additive QTLs. Exploration of the QTLs with epistatic effect resulted in the detection of 29 pairs of epistatic QTLs. To our information, this is only the second report of epistatic QTLs for seed longevity in bread wheat. We conclude that in addition to dense genetic maps, the epistatic interaction between loci should be considered to capture more variation which remained unnoticed in additive mapping.

Comparative analysis of wild type accessions reveals novel determinants of Arabidopsis seed longevity

Understanding the genetic factors involved in seed longevity is of paramount importance in agricultural and ecological contexts. The polygenic nature of this trait suggests that many of them remain undiscovered. Here, we exploited the contrasting seed longevity found amongst wild type Arabidopsis thaliana accessions to further understand this phenomenon. Concentrations of the antioxidant glutathione were consistently higher in longer-lived than shorter-lived accessions, supporting that redox poise plays a prominent role in seed longevity. However, high seed permeability, normally associated with shorter longevity, is also present in accessions with longer seed longevity. Transcriptome analysis indicated that the detrimental effect on longevity caused by seed coat permeability may be counterbalanced by higher levels of specific mRNAs stored in dry seed, particularly those of heat-shock proteins. Indeed, reverse genetics demonstrated that heat-shock factors HSF1A and 1B contributed to longevity. Furthermore, loss-of-function mutants of RNA-binding proteins, such as the stress-granule zinc-finger protein TZF9, or the spliceosome subunits MOS4 or MAC3A/MAC3B, extended seed longevity, positioning RNA as a novel player in the regulation of seed viability. mRNAs of proteins with putative relevance to longevity were also abundant in shorter-lived accessions, reinforcing the idea that resistance to ageing is determined by multiple factors.

Longevity of genepool maize seeds under model conditions

Aim. To determine genotypic features of seed longevity of different subspecieses of maize - carriers of the corresponding genes under model conditions. Methods. Accessions of the maize (Zea mays L.) gene pool: dent maize (subsp.indentata), semi-dent (subsp. semindentata), waxy (subsp.ceratina) wx, popcorn (subsp.everta), sweet maize (subsp.saccharata.) sh were investigated in the conditions of model experiment "accelerated aging". Results. The seed longevity of studied maize genotypes was established in the conditions of model experiment on indicators of germination energy, seed germination and morphophysiological indexes of sprouting. The applied conditions of accelerated aging had a negligible effect on the studied parameters, which corresponded to the initial stages of seed aging. Variations in morphophysiological indexes were observed. Conclusions. The highest sensitivity to accelerated aging was found for sweet (sh) and waxy maize (wx). Variation of morphophysiological parameters of seedlings in experimental and control variants, seed longevity of the studied varieties are discussed.Keywords: gene pool, seeds, maize, subspecies, longevity.

Assessment of Genetic Diversity Among Chinese High-Oleic Peanut Genotypes Using Miniature Inverted-Repeat Transposable Element Markers

As compared with normal-oleic peanut, high-oleic peanut proved to be heart-healthier, and had prolonged shelf life and extended seed longevity. However, there have concerns about the genetic diversity of present-day high-oleic peanut cultivars, which relied heavily on high-oleic donors with F435 type FAD2 mutations. In the study, a total of 104 high-oleic peanut cultivars/lines/mutants from main breeding teams in China were used to assess their genetic diversity with AhMITE markers. Of all the 31 cultivars tested, those from CTW team had the highest genetic variability. Again, of all the 73 lines studied, those from CTW team ranked first in genetic diversity. As compared with cultivars from CTW and C&Y teams, greater genetic diversity was detected in new lines of both teams, indicating that recent breeding efforts had resulted in improved genetic diversity in high-oleic peanut.

Seed Longevity and Germination Behaviour in Eugenia roxburghii

Eugenia roxburghii is an evergreen graceful shrub with a tremendous potential as garden plant. As a part of ex-situ conservation and popularization of the species, seed longevity was studied by understanding the relationship of seed viability with respect to different moisture contents and storage temperature. Seeds are recognized as recalcitrant, being desiccation as well as chilling sensitive. During hermetic storage, seeds stored at 300C/70%RH retained viability for about 5 months and 4 months in 200C/20% RH. Seeds can be best stored for five months in laboratory conditions.

Osmo-priming in tomato seeds down-regulates genes associated with stress response and leads to reduction in longevity

Tomato seeds subjected to osmo-priming show fast and more uniform germination. However, osmo-priming reduces seed longevity, which is a complex seed physiological attribute influenced by several mechanisms, including response to stress. Thus, to have new insights as to why osmo-primed tomato seeds show a short life span, we performed a transcript analysis during their priming. For that, we performed gene expression studies of the heat-shock protein family genes that were previously reported to be associated with the enhancement of longevity in primed tomato seeds. Physiological assays of germination, vigour and longevity tests were used to support the data. The results show that the short life span of osmo-primed tomato seeds is related to the decrease in the expression of transcripts associated with response to stress during the priming treatment. These results are important because they add information regarding which seed longevity mechanisms are impacted by the priming treatment. In parallel, it will allow the use of these genes as markers to monitor longevity in osmo-primed tomato seeds.