Exploring Host Resistance against Chilli Leaf Curl Disease in a Tolerant Chilli Genotype.

In tropical countries, combating leaf curl disease in hot peppers has become important in improvement programs. Leaf curl disease is caused by whitefly (Bemisia tabaci) transmitted begomoviruses, which mainly include chilli leaf curl virus (ChiLCV). However, multiple begomoviruses have also been found to be associated with this disease. The Capsicum annuum line, DLS-Sel-10, was found to be a tolerant source against this disease during field screening. In this study, we characterized the resistance of DLS-sel-10 against chilli leaf curl virus (ChiLCV) in comparison to the susceptible cultivar Phule Mukta (PM), focusing on the level, stage, and nature of resistance. Comprehensive investigations involved screening of DLS-Sel-10 against the whitefly vector ChiLCV. The putative tolerant line displayed reduced virus infection at the seedling stage, with increasing resistance during vegetative, flowering, and fruiting stages. Both DLS-Sel-10 and PM could be infected with ChiLCV, although DLS-Sel-10 remained symptomless. Insect feeding assays revealed DLS-Sel-10 as a less preferred host for whiteflies compared to PM. In conclusion, DLS-Sel-10 demonstrated tolerance not only to ChiLCV but also served as an unfavorable host for the whitefly vector. The study highlighted an age-dependent increase in tolerance within DLS-Sel-10, showcasing its potential for effective leaf curl disease management in chilli.

Foliar application of gamma radiation processed chitosan triggered distinctive biological responses in sugarcane under water deficit stress conditions.

Chitosan, being one of the most promising biological macromolecules, has an immense scope in agriculture to boost crop growth and defense responses. In this study, chitosan was exposed to gamma rays in order to obtain a low molecular weight derivative. Viscometric characterization showed a sharp decrease in molecular weight and FTIR based analysis confirmed retention of structural integrity of the polymer upon gamma irradiation. Assessments of various physiological and biochemical attributes were carried out on sugarcane plantlets that were subjected to progressive water deficit stress. The irradiated chitosan was found to differentially ameliorate water deficit stress tolerance against that of normal chitosan through positive modulation of various gas exchange parameters alongside significant improvement in relative tissue water content, SOD activity, soluble sugars and adenine energetics. Furthermore, application of irradiated chitosan significantly reduced cell membrane damage, lipid peroxidation, H2O2 and free-proline accumulations. This is the first report on the use of gamma irradiated chitosan to alleviate water deficit stress tolerance in sugarcane. Overall comparative assessments showed that differential plant responses were triggered upon foliar application of normal and gamma irradiated chitosan in sugarcane plants grown under water deficit stress conditions.

Gamma irradiation induced effects on in vitro shoot cultures and influence of monochromatic light regimes on irradiated shoot cultures of Dendrobium sonia orchid.

The effects of gamma radiation and monochromatic lights on growth of in vitro shoot cultures of orchid, Dendrobium sonia, were investigated. The gamma irradiated shoot cultures grown under white, blue, yellow and red monochromatic lights exhibited differential growth pattern. Shoot cultures gamma irradiated at 15-45 Gy showed reduced shoot length, fresh weight and leaf area. The monochromatic light significantly influenced survival rate and growth of irradiated shoots. The yellow and red light treatments positively influenced survival of gamma irradiated shoots with significant increase in fresh weight, shoot length and chlorophyll content. Yellow light was found to be most effective as leaf area was increased across the radiation dose range (15-100 Gy) compared to red light. The results demonstrated that the method of post-irradiation exposure could be useful to improve growth of gamma irradiated in vitro shoots, and help to recover orchid mutants with novel modifications.

Spatial distribution and dynamics of sucrose metabolising enzymes in radiation induced mutants of sugarcane.

Sucrose metabolism in various source and sink organs of developing sugarcane (Saccharum officinarum L.) plant is accompanied with continuous synthesis and cleavage. In this regard, the involvement of four major enzymes viz. sucrose synthase (SS), sucrose phosphate synthase (SPS), soluble acid (SAI) and neutral invertases (NI) is considered crucial. In this study, we have analysed in vivo enzymatic activity of 12th month old field grown radiation-induced sugarcane mutants identified for sucrose accumulation. The mutants showed significant differences in the spatial enzymatic regulation in leaves, immature and mature internodes; SPS and SS activities were found highest in high sucrose accumulating mutants (AKTS-02 and AKTS-20) along with lower levels of SAI activity. Overall positive correlation of SPS, SS and negative correlation of SAI, NI activities with sucrose content of the respective tissue types was observed. The SPS activity was found strongly associated with sucrose content in leaves (r(2) = 0.558) and internodes (r(2) = 0.514), whereas, the SAI activity was found significant in leaves (r(2) = 0.379) and weakly associated in internodal tissues (r(2) = 0.248). However, the associations were found to be non-significant for SS and NI activities in both leaves and internodes. Despite this, the differences in the SPS and SAI activities (SPS-SAI) in leaves (r(2) = 0.828) and internodal tissues (r(2) = 0.619) had shown greater influence on net sucrose synthesis and accumulation. To summarize, our results suggest differential sugar metabolism in the induced mutants and that such contrasting mutant germplasm with a relatively uniform genetic makeup can be useful in molecular studies on sucrose accumulation.