Regeneration potential of seedling explants of chilli (Capsicum annuum)

A study was conducted with hypocotyl, cotyledon and shoot tip of chilli as explants for regeneration on MS medium supplemented with different concentrations and combinations of auxins and cytokinins. Regeneration potential was determined by two ways. One is regeneration of shoot via callus formation from hypocotyls and cotyledon explants; another was direct shoot regeneration from shoot tip explant. The highest callus was induced from hypocotyl in a combination of BAP (5.0 mgL-1) with NAA (0.1 mgL-1) and cotyledon in a combination of BAP (5.0 mgL-1) with IAA ((1.0 mgL-1). The callus induction as well as shoot initiation was higher in hypocotyls than cotyledon. Shoot tips regenerated into plantlets directly with sporadic small callus at the base. Shoot elongation was accelerated by using additional supplementation of GA3 and AgNO3. Regenerated shoots rooted best on the MS medium supplemented with 0.1 mg L-1 NAA + 0.05 mg L-1 IBA

In vitro clonal propagation of the neem tree (Azadirachta indica A. Juss.)

A study was conducted with root and shoot tip explants of neem to develop an efficient protocol of regeneration. Shoot tips and root tips from 10 - 20 days old seedlings of neem were cultured on Murashige and Skoog’s (MS) medium supplemented with different concentrations and combinations of BAP (0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 mg l-1) and NAA (0.0 and 0.05 mg l-1). Shoot buds were initiated from the both explants. The highest percentage of regeneration was found from shoot tip but the highest average number of shoots/explants was found from root tip explants. The regenerated shoots were further subcultured and later could be rooted ona medium supplemented with different concentrations and combinations of IBA and IAA and complete plants could be obtained. The rooted plants were transplanted to pots for hardening

Changes in gene expression during germination reveal pea genotypes with either 'quiescence' or 'escape' mechanisms of waterlogging tolerance

<p>Waterlogging causes germination failure in pea (<em>Pisum sativum</em> L.). Three genotypes (BM-3, NL-2 and Kaspa) contrasting in ability to germinate in waterlogged soil were exposed to different durations of waterlogging. Whole genome RNAseq was employed to capture differentially expressing genes. The ability to germinate in waterlogged soil was associated with testa colour and testa membrane integrity as confirmed by electrical conductivity measurements. Among the most differentially regulated genes, upregulated gene tyrosine protein kinase responsible for metabolic regulation and downregulated LOX5 involved in fat metabolism indicated energy preservation in tolerant Kaspa, while in the other tolerant NL-2 subtilase family protein and PNC2 involved in protein and fat metabolism respectively showed upregulated expression suggesting energy utilization during waterlogging. By contrast, in sensitive genotype BM-3 high upregulation was recorded for the kunitz-type trypsin/protease inhibitor whose role is blocking the activity of protein metabolism leading to excessive lipid metabolism causing membrane leakage and subsequent seed damage. Pathway analyses based on gene ontologies showed seed storage protein metabolism as upregulated in tolerant genotypes and downregulated in the sensitive genotype. Understanding the tolerance mechanism provides a platform to breed for adaptation to waterlogging stress at germination in pea. </p

Changes in gene expression during germination reveal pea genotypes with either 'quiescence' or 'escape' mechanisms of waterlogging tolerance

<p>Waterlogging causes germination failure in pea (<em>Pisum sativum</em> L.). Three genotypes (BM-3, NL-2 and Kaspa) contrasting in ability to germinate in waterlogged soil were exposed to different durations of waterlogging. Whole genome RNAseq was employed to capture differentially expressing genes. The ability to germinate in waterlogged soil was associated with testa colour and testa membrane integrity as confirmed by electrical conductivity measurements. Among the most differentially regulated genes, upregulated gene tyrosine protein kinase responsible for metabolic regulation and downregulated LOX5 involved in fat metabolism indicated energy preservation in tolerant Kaspa, while in the other tolerant NL-2 subtilase family protein and PNC2 involved in protein and fat metabolism respectively showed upregulated expression suggesting energy utilization during waterlogging. By contrast, in sensitive genotype BM-3 high upregulation was recorded for the kunitz-type trypsin/protease inhibitor whose role is blocking the activity of protein metabolism leading to excessive lipid metabolism causing membrane leakage and subsequent seed damage. Pathway analyses based on gene ontologies showed seed storage protein metabolism as upregulated in tolerant genotypes and downregulated in the sensitive genotype. Understanding the tolerance mechanism provides a platform to breed for adaptation to waterlogging stress at germination in pea. </p