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T. amplexicaule Roth. has been investigated phytochemically for biologically active constituents from the benzene extract. This yielded a mixture of terpenoids: beta-sitosterol, alpha-amyrin, lupeol, hexacosanoic acid, ceryl alcohol and hexacosane. The sequential extracts, isolated terpenoids and reference antibiotics were screened for their possible bioactivities against selected pathogenic bacteria, Escherichia coli, Staphylococcus aureus and fungi, Aspergillus flavus and Penicillium chrysogenum etc. Out of the sequential extracts, the benzene extract was more potent against S. aureus (IZ = 10.36) and R. phaseoli (IZ = 10.69). The inhibition zones of isolated terpenoids were also recorded and the activity index was calculated and it was found that hexacosane was more active (IZ = 13.39) against E. coli and hexacosanoic acid had greater activity against A. flavus (IZ = 11.56). The present study deals with antimicrobial screening of sequential extracts and isolated terpenoids.

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Trichoderma spp., are saprophytic fungi that can improve plant growth through increased nutrient acquisition and change in the root architecture. In the present study, we demonstrate that Trichoderma asperellum T42 mediate enhancement in host biomass, total nitrogen content, nitric oxide (NO) production and cytosolic Ca2+ accumulation in tobacco. T42 inoculation enhanced lateral root, root hair length, root hair density and root/shoot dry mass in tobacco under deprived nutrients condition. Interestingly, these growth attributes were further elevated in presence of T42 and supplementation of NO3- and NH4+ nutrients to tobacco at 40 and 70 days, particularly in NO3- supplementation, whereas no significant increment was observed in nia30 mutant. In addition, NO production was more in tobacco roots in T42 inoculated plants fed with NO3- nutrient confirming NO generation was dependent on NR pathway. NO3- dependent NO production contributed to increase in lateral root initiation, Ca2+ accumulation and activities of nitrate transporters (NRTs) in tobacco. Higher activities of several NRT genes in response to T42 and N nutrients and suppression of ammonium transporter (AMT1) suggested that induction of high affinity NRTs help NO3- acquisition through roots of tobacco. Among the NRTs NRT2.1 and NRT2.2 were more up-regulated compared to the other NRTs. Addition of sodium nitroprusside (SNP), relative to those supplied with NO3-/NH4+ nutrition and T42 treated plants singly, and with application of NO inhibitor, cPTIO, confirmed the altered NO fluorescence intensity in tobacco roots. Our findings suggest that T42 promoted plant growth significantly ant N content in the tobacco plants grown under N nutrients, notably higher in NO3-, providing insight of the strategy for not only tobacco but probably for other crops as well to adapt to fluctuating nitrate availability in soil.

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Aims: To investigate the efficacy of Trichoderma harzianum NBRI-1055