Linseed (Linum usitatissimum L.) genetic resources for climate change intervention and its future breeding

Linseed or flax (Linum usitatissimum L.), a multiple purpose crop valued for its seed oil, fibre, probiotic and nutraceutical properties, is adapted to different environments and agro-ecologies. Modern breeding techniques using only limited number of selected varieties have resulted in a loss of specific alleles and thus, reduction in total genetic diversity relevant to climate-smart agriculture. However, well-curated collections of landraces, wild linseed accessions and other Linum species exist in the gene banks and are important sources of new alleles. This review is primarily focused on the studies of genetic diversity of linseed species and evaluation related to tolerance to abiotic and biotic stress factors that could be useful for improving linseed through future promising breeding programs in addition to briefly discussing different morphotypes and nutraceutical importance. Wide diversity in linseed germplasm indicates a considerable potential for improving this crop for both agronomic and quality traits required for developing climate-resilience tailored to specific environments. Recent release of the flax genome sequence coupled with wide range of genomic and analytical tools in public domain has furthered understanding of molecular mechanisms for detailed study of the genes underlying flax adaptation to stress and diversity in commercially important accessions. Important climate related traits and their constituent genes are presented and key developments for the future highlighted emphasizing the urgent need to increase the use of genetically diverse germplasm to meet the emerging challenges in agricultural production and to conserve valuable genetic resources for the future

Activities of sucrose to starch metabolizing enzymes during grain filling in late sown wheat under water stress

Tolerance to water deficit in relation to activities of sucrose-to- starch metabolizing enzymes and starch accumulation was studied in the grains of contrasting wheat (Triticum aestivum L.) genotypes (WH1021 and WH1080; tolerant) and (WH711 and HD2687; susceptible) under late planting conditions. The activities of starch metabolizing enzymes i.e. sucrose synthase (SuSase), ADP-glucose pyrophosphorylase (AGPase), soluble starch synthase (SSS) and starch branching enzymes (SBE) were substantially enhanced by water deficit in all genotypes at early to mid-grain filling stage showing peaks at 14 to 21 days after anthesis (DAA); while decreased significantly at mid-late grain filling stage with maximum decline at 35 DAA. Activities of all the enzymes under study showed maximum decline in activity (28.4–60%) in susceptible genotype WH711; whereas WH1021 proved to be most tolerant one with minimum decline in enzyme activity (14.9–32.8%). Starch content was also markedly reduced (21%) in WH711 due to drought while WH1021 reported 12% decline corresponding well with enzyme activity. A faster pre-mature cessation of starch deposition occurred in susceptible wheat genotypes compared to tolerant ones. A significant and positive correlation of the enzyme activities with starch accumulation (r = 0.491–0.555 at P0.05 for SuSase, AGPase, SSS and r = 0.638 at P0.01 for SBE) under well watered conditions indicated that enhancing the activities of the enzymes would lead to increase in starch accumulation and thus faster grain filling. Genotype WH1021 proved to be most efficient based on comparatively higher enzyme activity and least yield penalty under late planting conditions combined with water scarcity

Phenotypic characterization, genetic diversity assessment in 6,778 accessions of Barley ( Hordeum vulgare L. ssp. vulgare) germplasm conserved in national genebank of India and development of a core set

The entire collection of cultivated barley germplasm accessions conserved in the Indian National Genebank (INGB) was characterized for nine qualitative and 8 quantitative traits to assess the nature and magnitude of prevailing genetic variability and to develop a core set. A wide range of variability was observed for days to spike emergence (51–139 days), days to physiological maturity (100–152 days), plant height (45.96–171.32 cm), spike length (3.44–13.73 cm), grain number/spike (10.48–82.35), and 100-grain weight (1.20–6.86 g). Initially, seven independent core sets were derived using 3 core construction tools– MSTRAT, PowerCore, and Core Hunter 3 by employing the maximization method, heuristic sampling, and optimisation of average genetic distances, respectively. The core set-3 generated by Core Hunter 3 by simultaneous optimisation of diversity and representativeness, captured maximum genetic diversity of the whole collection as evident from the desirable genetic distance, variance difference percentage (VD; 87.5%), coincidence rate of range (CR; 94.27%) and variable rate of coefficient of variance (VR; 113.8%), which were more than threshold value of VD (80%), CR (80%), and VR (100%) required for good core collection. The coefficient of variation and Shannon–Weaver diversity indices were increased in the core set as compared with the whole collection. The low value of Kullback-Leibler distance (0.024–0.071) for all traits and quantile-quantile plots revealed a negligible difference between trait distribution patterns among the core set and entire assembly. Correlogram revealed that trait associations and their magnitude were conserved for most of the traits after sampling of the core set. The extraction of the INGB barley core set and identification of promising accessions for agronomically important traits in different genetic backgrounds will pave the way for expedited access to genetically diverse and agronomically important germplasm for barley breeding

Genetic dissection of thousand-seed weight in linseed (Linum usitatissimum L.) using multi-locus genome-wide association study

Flaxseed/linseed is an important oilseed crop having applications in the food, nutraceutical, and paint industry. Seed weight is one of the most crucial determinants of seed yield in linseed. Here, quantitative trait nucleotides (QTNs) associated with thousand-seed weight (TSW) have been identified using multi-locus genome-wide association study (ML-GWAS). Field evaluation was carried out in five environments in multi-year-location trials. SNP genotyping information of the AM panel of 131 accessions comprising 68,925 SNPs was employed for ML-GWAS. From the six ML-GWAS methods employed, five methods helped identify a total of 84 unique significant QTNs for TSW. QTNs identified in ≥ 2 methods/environments were designated as stable QTNs. Accordingly, 30 stable QTNs have been identified for TSW accounting up to 38.65% trait variation. Alleles with positive effect on trait were analyzed for 12 strong QTNs with r2 ≥ 10.00%, which showed significant association of specific alleles with higher trait value in three or more environments. A total of 23 candidate genes have been identified for TSW, which included B3 domain-containing transcription factor, SUMO-activating enzyme, protein SCARECROW, shaggy-related protein kinase/BIN2, ANTIAUXIN-RESISTANT 3, RING-type E3 ubiquitin transferase E4, auxin response factors, WRKY transcription factor, and CBS domain-containing protein. In silico expression analysis of candidate genes was performed to validate their possible role in different stages of seed development process. The results from this study provide significant insight and elevate our understanding on genetic architecture of TSW trait in linseed

Healthy Barley

46-47Barley has more dietary fibre and protein content as compared to other staple cereals especially in comparison to wheat and it is very cheap and easily available all over the world

Grain yield in wheat as affected by short periods of high temperature, drought and their interaction during pre- and post-anthesis stages

Drought and high temperature are especially considered as key stress factors with high potential impact on crop yield. The aim of this study was to investigate the effect of short periods of high temperature, drought and their combination at different growth stages of plant under controlled conditions. The effects of high temperature and drought on grain yield were additive. However, high temperature increased the degree of water stress and the combined effects of drought and high temperature were much more severe than those of each individual treatment. High temperature and drought applied at post- anthesis shortened duration of maturation, grain filling duration and reduced grain yield, mean grain weight, grain number and thousand-grain weight

High temperature, drought and their interaction induced protein alterations in sensitive and tolerant wheat varieties

Two contrasting wheat (Triticum aestivum L.) cultivars WH730 (high temperature tolerant) and UP2565 (high temperature sensitive) were tested for differential response to combined and individually applied high temperature (HT) and drought (D) stress at seedling stage for peptide profile. Initial profile of the stress induced peptides was outlined via SDS electrophoresis of leaf extracts. Electrophoretic pattern of proteins revealed expression of new bands as well as disappearance of certain others in HT, D and interactive HT+D stress treated and revived samples in both wheat varieties relative to untreated control samples. Some of the bands that appeared in stress treated seedlings were also present after revival indicating their protective role, while some new peptides synthesized after stress but disappeared after revival period may be designated true stress proteins. However, all the plants from heat, drought and their interactive stress treatments continued to grow during recovery period. This suggests that these proteins and other newly synthesized proteins may have protective effects at high temperature (40°C) and water scarcity and provide plants for healthy growth during the recovery period. Furthermore, elucidating the functions of proteins expressed by genes in stress tolerant and susceptible plants may provide important information for designing new strategies for crop improvement

Comprehensive characterization of protease inhibiting gene family, cis-regulatory elements, and protein interaction network in linseed and their expression upon bud fly infestation

Abstract Linseed, also known as flax is an important oilseed crop with many potential uses in paint, textile, food and pharmaceutical industries. Susceptibility to bud fly (Dasyneura lini Barnes) infestation is a serious biotic concern leading to severe yield penalty in linseed. Protease inhibitors (PIs) are potential candidates that activate during the insect-pest attack and modulate the resistance. In the present study, we explored the PI candidates in the linseed genome and a total of 100 LuPI genes were identified and grouped into five distinct subgroups. The analysis of cis-acting elements revealed that almost all LuPI promoters contain several regulatory elementary related to growth and development, hormonal regulation and stress responses. Across the subfamilies of PIs, the specific domains are consistently found conserved in all protein sequences. The tissue-specific in-silico expression pattern via RNA-seq revealed that all the genes were regulated during different stress. The expression through qRT-PCR of 15 genes revealed the significant up-regulation of LuPI-24, LuPI-40, LuPI-49, LuPI-53, and LuPI-63 upon bud fly infestation in resistant genotype EC0099001 and resistant check variety Neela. This study establishes a foundation resource for comprehending the structural, functional, and evolutionary dimensions of protease inhibitors in linseed

Influence of GA3 (gibberellic acid) and Ca(calcium) on root trait variation and osmotic potential of linseed (Linum usitatissimum L.) under chloride-dominated salinity

Linseed (Linum usitatissimum) is a versatile crop cultivated for its seeds, which are valuable source of ω-3 fatty acids. It adversely affected by soil salinity, as high salt levels can hinder their growth and reduce yields. To assess the potential for mitigating the adverse effects of high salinity concentrations, enhancing the resilience of  three genotypes (Shekhar, Sheela, and Kartika) of linseed plants, this research aimed to find out the impact of Gibberellic acid (GA3) and Calcium (Ca) on various aspects of root morphology, osmotic potential of linseed, under varying levels of Cl- dominated salinity. The study employed three salinity levels (0, 5, and 10 dSm-1) and exogenous application of  10−6 M GA3 and/or 10 mg CaCl2 kg-1 in potted plants.The findings indicated that increasing salinity stress significantly (p≤0.05) affected root parameters, including total surface area(43.45%), average diameter(42.06%), total projected area(44.45%),   length per volume (66.23%), root length, total root volume (73.23%), tips, forks,fine roots, and osmotic potential(66.67%). Correlations among linseed genotypes were observed between various root morphology and osmotic potential parameters. The application of GA3 and Ca effectively ameliorated the impact of salinity stress at its highest level (10 dSm-1), resulting in increased root parameters while decreasing the osmotic potential (Ψs). Both GA3 and Ca treatments significantly influenced root architecture and maintained optimal osmotic potential. The chloride-dominated salinity exerted inhibitory effects on all three genotypes’ (Shekhar, Sheela, and Kartika) root growth parameters while applying GA3 and Ca successfully mitigated these effects, enhancing root growth.