Trends and advances in pre- and post-harvest processing of linseed oil for quality food and health products

Utilization of 16Sr RNA and secA genes for molecular discernment of 'Candidatus Phytoplasma australasiaticum' strain associated with linseed germplasm in India

The growing prevalence of phytoplasma associated symptoms on linseed or flax (Linum usitatissimum L.) germplasm at Indian Council of Agricultural Research- National Bureau of Plant Genetic Resources (ICAR-NBPGR) fields was noticed during the 2019-22 growing seasons. The characteristic phytoplasma symptoms of phyllody, stem fasciation, stunting, along with floral and capsule malformations were observed in 41 linseed accessions grown at experimental fields of ICAR-NBPGR, Delhi. During 3 years, the presence of phytoplasma in symptomatic linseed accessions was confirmed by nested-PCR assays utilizing 16S rRNA and secA gene-specific primers. The 16S rRNA and secA gene sequences of linseed phytoplasma strains from the representative symptomatic 41 linseed accessions exhibited 100% sequence identity among themselves and 99.93% and 99.82% sequence homology with reference strain, 'Candidatus Phytoplasma australasiaticum' (GenBank Accession: Y10097). Phylogenetic analysis of 16S rRNA and secA gene sequences clustered the linseed isolates with the peanut witches' broom group belonging to 'Ca. P. australasiaticum' strains. The virtual RFLP analysis of 16S rRNA F2nR2 fragment (~1.2 kb) of linseed phytoplasma strains further classified it into 16Sr group II, subgroup D. Our results suggested confirmation of the association of 'Ca. P. australasiaticum' strain (16SrII-D) in the linseed germplasm accessions from North India, which is the first report from India. The phytoplasma infection also reduced the growth and yield parameters of two linseed accessions (IC0498748 and EC0718851).

Effect of GA3 and calcium on growth, biochemical, and fatty acid composition of linseed under chloride-dominated salinity

The accumulation of salts in soil is an environmental threat affecting plant growth and crop yield. Linseed or flax is an ancient crop that has multifarious utilities in terms of industrial oil, textile fiber, and products. Salt susceptibility adversely affects linseed production, particularly to meet the growing demand for nutritional and nutraceutical products. In the present study, the ameliorative potential of gibberellic acid (GA3) and calcium (Ca2+) in mitigating the adverse effects of chloride-dominated salinity stress on the growth and physiological and biochemical processes in linseed was determined. Severe salinity treatment (10 dSm-1) resulted in stunted growth of tested linseed genotypes causing a significant reduction in biomass while proline content, phenol, H2O2, lipid peroxidation, and DPPH activity were increased in comparison to control. The exogenous application of 10-6 M GA3 and/or 10 mg CaCl2 kg-1 was found to mitigate the adverse effects of salinity stress. The mitigation was accomplished through the improvement of growth indicators, increased osmoprotectants such as proline and phenol content, stimulating DPPH activity, and reduction of H2O2 content and lipid peroxidation. The comparative evaluation of different saline treatments imposed individually and in combination with GA3 and Ca2+ revealed that combined GA3 and Ca2+ application exhibited synergistic effects and was most effective in mitigating the negative impacts of salt stress. The present study unravels the ameliorative role of GA3 and Ca2+ (individual or combined) in the physiologic-biochemical adaptive response of linseed plants grown under chloride-dominated salinity and thus aids in a better understanding of the underlying tolerance mechanisms of plants to withstand stress in saline environments.