Phenazine 1-carboxylic acid Producing Seed Harbored Endophytic Bacteria from Cultivated Rice Variety of Kerala and Its Broad Range Antagonism to Diverse Plant Pathogens.

Endophytic microorganisms residing within the diverse parts of plants play a significant role in the plant growth and defense response. In the case of the vertically transmitted seed-borne endophytes, they form the promising initiator of the juvenile plant microbiome by supporting the growth and establishment of the seedlings. Hence, the current study emphasizes the isolation and screening of plant beneficial traits of seed endophytes from the cultivated rice variety Jyothi of Kerala, India. Among the 14 bacterial endophytes obtained in the study, the isolate S3 was found to have promising activity against the phytopathogens such as Fusarium oxysporum, Pythium aphanidermatum, Pythium myriotylum, Phytophthora infestans, Rhizoctonia solani, Colletotrichum acutatum, and Sclerotium rolfsii. The isolate S3 was further identified as Paenibacillus polymyxa by the 16S rRNA-based sequence analysis. Furthermore, the isolate was confirmed for its capability for hydrogen cyanide (HCN) production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, biofilm formation, and nitrogen fixation. The P. polymyxa S3 was also found to have the potential to provide post-harvest protection to the rice kernels from Sclerotium rolfsii. By the LC-MS/MS analysis, the organism was confirmed for the production of phenazine 1-carboxylic acid which could be the prime chemical basis of its antifungal activity. The in vivo plant growth evaluation has also demonstrated the root length enhancement effect of P. polymyxa S3 in Vigna unguiculata. Here, the root length of P. polymyxa S3-treated plant was enhanced to 12.44 ± 0.58223 cm when compared with distilled water control (10.261 ± 0.38151 cm) and the observed change was statistically significant as per the analysis of variance at P value less than 0.05. Based on all these properties, the isolated P. polymyxa S3 could be considered as a promising agent to be used for the development of competent plant probiotic formulations.

Purification and partial characterization of low molecular weight vicilin-like glycoprotein from the seeds of Citrullus lanatus.

The watermelon (Citrullus lanatus) seeds are highly nutritive and contain large amount of proteins and many beneficial minerals such as magnesium, calcium, potassium, iron, phosphorous, zinc etc. In various parts of the world, C. lanatus seed extracts are used to cure cancer, cardiovascular diseases, hypertension, and blood pressure. C. lanatus seed extracts are also used as home remedy for edema and urinary tract problems. In this study, we isolated protein fraction of C. lanatus seeds using various protein separation methods. We successfully purified a low molecular weight vicilin-like glycoprotein using chromatographic methods followed by SDS-PAGE and MALDI-TOF/MS identification. This is the first report of purification of a vicilin like polypeptide from C. lanatus seeds. In next step, we extracted mRNA from immature seeds and reverse transcribed it using suitable forward and reverse primers for purified glycoprotein. The PCR product was analysed on 1% agarose gel and was subsequently sequenced by Dideoxy DNA sequencing method. An amino acid translation of the gene is in agreement with amino acid sequences of the identified peptides.

Identification of a novel and potent inhibitor of phospholipase A(2) in a medicinal plant: crystal structure at 1.93Å and Surface Plasmon Resonance analysis of phospholipase A(2) complexed with berberine.

Crystal of Russell Viper venom phospholipase A(2) complexed with an isoquinoline alkaloid, berberine from a herbaceous plant Cardiospermum halicacabum, was prepared and its structure was solved by X-ray crystallography. The crystal diffracted up to 1.93Å and the structure solution clearly located the position of berberine in the active site of the enzyme. Two hydrogen bonds, one direct and the other water mediated, were formed between berberine and the enzyme. Gly 30 and His 48 made these two hydrogen bonds. Additionally, the hydrophobic surface of berberine made a number of hydrophobic contacts with side chains of neighboring amino acids. Surface Plasmon Resonance studies revealed strong binding affinity between berberine and phospholipase A(2). Enzyme inhibition studies proved that berberine is a competitive inhibitor of phospholipase A(2). It was inferred that the isoquinoline alkaloid, berberine, is a potent natural inhibitor of phospholipaseA(2).