Papaya (Carica papaya L.) is one of the important fruits cultivated in the tropical and subtropical regions are widely prone to the post-harvest anthracnose disease. A sum of ten isolates of Colletotrichum gloeosporioides were collected and identified through morphological and molecular method. Morphological characterization of the isolates revealed a wide variation among the isolates with respect to colony colour, topography, margin, pigmentation and zonation. The ITS gene region and the specific primer, MKCgF coupled with ITS-4, which generated amplicons of size 560 bp and 380 bp respectively for C. gloeosporioides. The amplicon (560 bp) of virulent strain Cg1 was partially sequenced [MF062699]. In order to formulate eco-friendly management practices, the in vitro screening of different biocontrol agents viz., Bacillus spp., Pseudomonas spp., plant extracts and essential oils were tested against the C. gloeosporioides. Based on the in vitro efficacy, Bacillus sp. (BSP1) and cinnamon oil were selected and further tested under field conditions as pre harvest spray and after harvest as fruit dipping. The experimental results revealed that pre-harvest spray with Bacillus sp. (BSP1) (5%) + post-harvest dipping with cinnamon oil (0.1%) recorded the lowest PDI of 3.25 when compared to control (70.36) and also increased the shelf life of papaya fruits up to 14 days. Our results show that this novel methodology of use a combination of biocontrol agent as pre-harvest spray and essential oils as post-harvest fruit dipping will protect against post-harvest anthracnose of papaya and use of chemical fungicides can be avoided.

The environment around the root in rhizosphere is a complex region where multiple interactions take place among soil, plant and microorganisms. Plant growth and architecture of entire plant, in fact depends upon the roots which provide sufficient amount of nutrients and water. Root tips while sensing the rhizosphere for availability nutrients counteract with array of harmful microorganisms in the soil. In order to protect from these stresses plant roots have evolved specialized cells known as root border cells which act as front line defence mechanism in rhizosphere. Border cells are individual or bunch of programmed viable cells released from root tip which forms protective sheath between root and external environment. Border cells secret hydrated mucilage that contains antimicrobial compounds and extracellular DNA which governs the behaviour of microbiome in the soil. Production of border cell is regulated by number of factors such as phytohormones, PME enzyme and transcription factor NLP7. Plant breeding and genetic engineering could be used to exploit border cells defence mechanism as a new avenue for disease control. This review summarizes about the importance, properties of border cells, mechanism, and regulation of border cells production and role of RETs as element of plant defence.

The search for new Bacillus thuringiensis (Bt) strains is a continuous process and researchers are now focusing on finding toxin proteins that are toxic to pests of insect orders that are not reported. In the present study soil and insect cadaver samples were collected from North East India comprising the states of Assam, Tripura and Mehhalaya and native Bt were isolated using standard protocols. At total of 30 Bt isolates were purified and characterized. Various types of crystal morphology were encountered that included bipyramidal, cuboidal, square, rhomboid, spherical and irregular. PCR analysis showed that diverse cry genes were expressed. The cry genes identified were Lepidoptera, Coleoptera and Diptera specific. Detected genes included cry1Ac, cry2A, cry4A, cry10A, cry16A, cry17A, cry19A, cry30Aa, cry44Aa, cry11A, cry4B, cry12A, cry8A and cry7A. Many of them were positive for Vip3A protein. The coleopteran specific Bt were evaluated against Sitophilus oryzae and Callosobruchus chinensis and NBAIR-AgBt6 was found to be toxic. The isolates are being further evaluated for use as biopesticides.(Article chronicle: