The abscisic acid receptor OsPYL6 confers drought tolerance to indica rice through dehydration avoidance and tolerance mechanisms.

Abscisic acid (ABA) is a key regulator of plant development and stress tolerance. Here we report functional validation of the ABA receptor OsPYL6 by constitutive and stress-inducible overexpression and RNAi silencing, in an indica rice cultivar 'Pusa Sugandh 2'. Overexpression of OsPYL6 conferred ABA hypersensitivity during germination and promoted total root length. Overexpression and RNAi silencing of OsPYL6 resulted in enhanced accumulation of ABA in seedlings under non-stress conditions, at least, in part through up-regulation of different 9-cis epoxycarotenoid dioxygenase (NCED )genes. This suggests that PYL6 expression is crucial for ABA homeostasis. Analysis of drought tolerance of OsPYL6 transgenic and wild type plants showed that OsPYL6 overexpression enhanced the expression of stress-responsive genes and dehydration tolerance. Transgenic rice plants overexpressing OsPYL6 with AtRD29A (Arabidopsis thaliana Responsive to Dehydration 29A) promoter also exhibited about 25% less whole plant transpiration, compared with wild type plants under drought, confirming its role in activation of dehydration avoidance mechanisms. However, overexpression of PYL6 reduced grain yield under non-stress conditions due to reduction in height, biomass, panicle branching and spikelet fertility. RNAi silencing of OsPYL6 also reduced grain yield under drought. These results showed that rice OsPYL6 is a key regulator of plant development and drought tolerance, and fine-tuning of its expression is critical for improving yield and stress tolerance.

Taxonomic identification and bioactive compounds characterization of Psilocybe cubensis DPT1 to probe its antibacterial and mosquito larvicidal competency.

Mushrooms have an important role in sustainability since they have long been used as valuable food source and traditional medicine around the world. Regrettably, they are among the most rigorously affected populations, along with several plants and animals, due to the destructive activities of mankind. Thus the authentication and conservation of mushroom species are constantly needed to exploit the remarkable potential in them. In this perspective, an attempt has been made to identify and assess the biological attributes of psychedelic mushrooms collected from Kodaikanal, Tamil Nadu, India. The macromorphological features of the psychedelic mushroom DPT1 helped its presumptive identification and the molecular characters depicted by DNA marker revealed its close relationship with the genus Psilocybe. Accordingly, the psychedelic mushroom was identified as Psilocybe cubensis DPT1 and its crude ethyl acetate extract on analysis revealed the occurrence of phytoconstituents like alkaloids, flavonoids, tannins, saponins and carbohydrates. Moreover, it exhibited 80% larvicidal activity against Culex quinquefasciatus mosquito at 800 ppm concentration and an array of antibacterial effects with utmost susceptibility of Proteus vulgaris, and the identification of bioactive compounds by different analytical techniques substantiate that the bioactivities might be due to the presence of phytochemicals. The results of the study indicated that the extract of P. cubensis DPT1 having notable antibacterial and mosquito larvicidal efficacies which could be probed further for the isolation of medicinally important as well as bio-control compounds.

In vitro regeneration from protocorms in Dendrobium aqueum Lindley - An imperiled orchid.

An efficient in vitro plant regeneration protocol from protocorms of Dendrobium aqueum was developed. The uniformly developed protocorms (in vitro origin) having shoot initials were cultured on half macro strength MS medium (1/2 MS) supplemented with cytokinins (BA, 2iP, KIN and TDZ) at 1, 3, 5, 7, 10 mg l-1, natural additives (BP and CW) at 1%, 3%, 5%, 7%, 10% and auxins (IBA, NAA, 2,4-D) at 1, 3, 5, 7, 10 mg l-1 to study their efficacy on complete plant development. A maximum of 9.4 shoots per explant were generated on 3 mg l-1 of NAA followed by 3% of BP (7.0 shoots). Shoot elongation (1.52 cm) was achieved on 1/2 MS medium fortified with NAA 7 mg l-1 followed by TDZ 7 mg l-1 (1.37 cm). Shoots cultured on 1/2 MS medium supplemented with IBA 5 mg l-1 produced an average of 8.75 roots per shoot, however the lengthiest roots (1.48 cm) were noted in NAA 7 mg l-1. Healthy rooted plantlets successfully acclimatized in ex vitro condition. The role of complete plantlet production by natural additives could be useful for conservation and cost effective commercial production of orchids.