Central Tuber Crops Research Institute

About: Central Tuber Crops Research Institute is a facility organization based out in Thiruvananthapuram, Kerala, India. It is known for research contribution in the topics: Starch & Fermentation. The organization has 475 authors who have published 587 publications receiving 10285 citations.

Molecular characterization and amplified ribosomal DNA restriction analysis of entomopathogenic bacteria associated with Rhabditis (Oscheius) spp.

Abstract: Bacterial strains associated with entomopathogenic nematodes (EPNs) Rhabditis (Oscheius) spp. were isolated from infected cadavers of Galleria mellonella. The obtained 18 isolates were subdivided into nine phylogenetically different genera based on comparative sequence analysis of their 16S rRNA genes. The isolates were affiliated to three different class namely γ-proteobacteria (Enterobacter, Proteus, Providencia, Pseudomonas, Stenotrophomonas), β-proteobacteria (Alcaligenes) and Bacilli (Bacillus, Enterococcus, Lysinibacillus). It was observed that Gram-positive strains (Bacilli) were more frequently associated with the EPN, whereas Gram-negative isolates were affiliated to six different genera with more genotypic diversity. Subsequently, all bacterial isolates used in this study were analyzed by amplified ribosomal DNA restriction analysis (ARDRA). Eight restriction endonucleases (CfoI, HinfI, RsaI, DdeI, Sau3AI, AluI, HaeIII, and MspI) were examined and a total of 15 different genotypes were obtained, forming two heterogenous main clusters after analysis by un-weighted pair-group method using arithmetic averages.

Cassava as an alternate host for multiplication of VAM fungi

Abstract: Cassava tuber skin contained VAM fungal spores, mycelial bits which embedded in between the layers and the cassava root system are non-specific to native or non-indigenous mycorrhizal fungus. Hence, an efficient strain of a VAM fungus can be multiplied in cassava and the cassava skin can be used for propagating VA-mycorrhizae in the field for crop production.

Purification and identification of two antifungal cyclic dipeptides from Bacillus cereus subsp. thuringiensis associated with a rhabditid entomopathogenic nematode especially against Fusarium oxysporum

Abstract: The cell-free culture filtrate of Bacillus cereus subsp. thuringiensis associated with an entomopathogenic nematode (EPN), Rhabditis (Oscheius) sp., exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by silica gel column chromatography to obtain two cyclic dipeptides (CDPs). The structure and absolute stereochemistry of this compound were determined based on extensive spectroscopic analyses (FABMS, (1)H NMR, (13)C NMR, (1)H-(1)H COSY, (1)H-(13)C HMBC) and Marfey's method. The compounds were identified as cyclo(D-Pro-L-Met) and cyclo(D-Pro-D-Tyr). CDPs showed significantly higher activity than the standard fungicide bavistin against agriculturally important fungi, viz., Fusarium oxysporum, Rhizoctonia solani and Penicillium expansum. The highest activity of 2 µg/ml by cyclo(D-Pro-D-Tyr) was recorded against F. oxysporum, a plant pathogen responsible for causing fusarium wilt followed by R. solani, a pathogen that causes root rot and P. expansum. To our knowledge, this is the first report on the isolation of these compounds from Rhabditis EPN bacterial strain Bacillus cereus subsp. thuringiensis.

Genetic Diversity Analysis in Taro Using Molecular Markers – An Overview

Abstract: Taro ( Colocasia esculenta L. (Schott.)) is an important root crop especially in the humid tropics and sub-tropics. It is one of the few crops that can adapt well to different agro-climatic conditions. Taro is thought to have been originated in the Indo-Malayan region probably in North Eastern India and Bangladesh. However, some studies suggest that there exists a parallel Pacific gene pool for taro, quite distinct from the Asian one. Due to the vegetative nature of the crop and as a result of fixing of somatic mutations, morphotypes are quite distinct even when they share the same genetic material. Hence, for breeding purposes, selection of the most divergent parents becomes difficult if one goes by morphological characterization alone. It is in this regard that molecular characterization attains its relevance. Here, the actual genetic diversity exhibited by the crop can be measured and utilized for breeding and conservation of genetic resources. Though a good amount of molecular work has been carried out in the Pacific and South-east Asian genepools, no systematic work has been undertaken in Indian taro germplasm collections, except for a few scattered reports. In this review, an attempt has been made to document thoroughly the major molecular markers used for the analysis of genetic diversity in taro and its application in the management of genetic resources.