Abstract
The present study reports the role of morphological, physiological and reproductive attributes viz. membrane stability index (MSI), osmolytes accumulations, antioxidants activities and pollen germination for heat stress tolerance in contrasting genotypes. Heat stress increased proline and glycine betaine (GPX) contents, induced superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione peroxidase (GPX) activities and resulted in higher MSI in PDL-2 (tolerant) compared to JL-3 (sensitive). In vitro pollen germination of tolerant genotype was higher than sensitive one under heat stress. In vivo stressed pollens of tolerant genotype germinated well on stressed stigma of sensitive genotype, while stressed pollens of sensitive genotype did not germinate on stressed stigma of tolerant genotype. De novo transcriptome analysis of both the genotypes showed that number of contigs ranged from 90,267 to 104,424 for all the samples with N50 ranging from 1,755 to 1,844 bp under heat stress and control conditions. Based on assembled unigenes, 194,178 high-quality Single Nucleotide Polymorphisms (SNPs), 141,050 microsatellites and 7,388 Insertion-deletions (Indels) were detected. Expression of 10 genes was evaluated using quantitative Real Time Polymerase Chain Reaction (RT-qPCR). Comparison of differentially expressed genes (DEGs) under different combinations of heat stress has led to the identification of candidate DEGs and pathways. Changes in expression of physiological and pollen phenotyping related genes were also reaffirmed through transcriptome data. Cell wall and secondary metabolite pathways are found to be majorly affected under heat stress. The findings need further analysis to determine genetic mechanism involved in heat tolerance of lentil.
Highlights
Lentil (Lens culinaris Medikus) is grown in relatively dry ecology where yield is mainly affected by various abiotic stresses
Plants of sensitive genotype showed marked wilting of leaves along with lodging of stems when compared to plants of tolerant one (Fig. 1)
This indicated that 3 d continuous heat exposure is sufficient to discriminate genotypes as tolerant or sensitive, in addition to the fact that the genotypes has already been selected from a whole spectrum of 119 genotypes by Singh et al.[1]
Summary
Lentil (Lens culinaris Medikus) is grown in relatively dry ecology where yield is mainly affected by various abiotic stresses. Heat stress may result in scorching and sunburn of leaves, accelerating leaf senescence; inhibition of root and shoot growth and seedling survival[1]. It reduces membrane stability index (MSI), which reflects leaching of ions due to plasma membrane injury under heat stress. Identification of molecular markers i.e. simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs), is a leading target of functional genomic studies. These markers are highly polymorphic, co-dominant, convenient, highly reproducible, stable and authentic. Newly identified markers can be utilized in molecular and comparative studies in other legumes as well
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call