Hydrogen sulphide and nitric oxide mitigate the negative impacts of waterlogging stress on wheat (Triticum aestivum L.)

Nitric oxide (NO) and hydrogen sulphide (H₂ S) are important gaseous signalling molecules that regulate key physiochemical mechanisms of plants under environmental stresses. A number of attempts have been made to improve waterlogging tolerance in plants, but with limited success. Having said that, NO and H₂ S are vital signalling molecules, but their role in mitigating waterlogging effects on crop plants is not well established. We investigated the efficacy of exogenous NO and H₂ S to alleviate waterlogging effects in two wheat cultivars (Galaxy-2013 and FSD-2008). Waterlogging produced a noticeable reduction in plant growth, yield, chlorophyll, soluble sugars and free amino acids. Besides, waterlogging induced severe oxidative damage seen as higher cellular TBARS and H₂ O₂ content. Antioxidant enzyme activity increased together with a notable rise in Fe²⁺ and Mn²⁺ content. Proline content was higher in waterlogged plants compared with non-waterlogged plants. In contrast, waterlogging caused a substantial decline in endogenous levels of essential nutrients (K⁺ , Ca²⁺ and Mg²⁺ ). Waterlogged conditions led to Fe²⁺ and Mn²⁺ toxicity due to rapid reduction of Fe³⁺ and Mn³⁺ in the soil. Exogenous NO and H₂ S significantly protected plants from waterlogging effects by enhancing the oxidative defence and regulating nutritional status. Besides, the protective effects of exogenous NO were more prominent as compared with effects of H₂ S. Further, we did not study the effect of H₂ S and NO on photosynthetic attributes and expression of stress-related genes. Therefore, future studies should examine the effects of H₂ S and NO on wheat physiology and gene expression under waterlogging.

Elevation in wildfire frequencies with respect to the climate change

Forests have been undergoing through immense pressure due to the factors like human activities; procurement of forest products and climate change which is a major factor influencing this pressure buildup on forests. Climate change and temperature increase caused by anthropogenic activities have notably affected forests and wildlife on a global scale. High temperature increases the soil-water evaporation, resulting in drier soils, and water loss in forest flora. The incidence of forest fires has doubled since 1984 and these are linked to global warming. Drought influences fuel moisture by bringing about physiological changes in forest vegetation leading to forest fires. Forest resilience is hampered because of temperature and drought stress at the developing stage of plant's life cycle leading to the shift in plant species in those areas. Forest fire incidences can be managed with proper management strategies such as sustainable, community and urban forest management. A careful monitoring of stress precursors, subsistence uses of forests, ecological education and planting of near native and new indigenous plant species are the tools that can aid in efficient forest management.

Genetic similarities and phylogenetic analysis of Muntjac (Muntiacus spp.) by comparing the nucleotide sequence of 16S rRNA and cytochrome B genome

This study aimed to identify the phylogenetic similarities among the muntjac (Muntiacus spp.). The phylogenetic similarities among seven major muntjac species were studied by comparing the nucleotide sequence of 16s rRNA and cytochrome b genome. Nucleotide sequences, retrieved from NCBI databases were aligned by using DNASTAR software. A phylogenetic tree was created for the selected species of muntjac by using the maximum likelihood method on MEGA7 software. The results of nucleotide sequences (16s rRNA) showed phylogenetic similarities between, the M. truongsonensis and M. rooseveltorum had the highest (99.2%) while the lowest similarities (96.8%) found between M. crinifrons and M. putaoensi. While the results of nucleotide sequences (Cty b) showed the highest similarity (100%) between M. muntjak and M. truongsonensis and the lowest s (91.5%) among M. putaoensis and M. crinifrons. The phylogenetic tree of muntjac species (16s rRNA gene) shows the main two clusters, the one including M. putaoensis, M. truongsonensis, M. rooseveltorum, and M. muntjak, and the second one including M. crinifrons and M. vuquangensis. The M. reevesi exists separately in the phylogenetic tree. The phylogenetic tree of muntjac species using cytochrome b genes shows that the M. muntjak and M. truongsonensis are clustered in the same group.

28-homobrassinolide regulates antioxidant enzyme activities and gene expression in response to salt- and temperature-induced oxidative stress in Brassica juncea

Brassinosteroids (BRs) are a group of naturally occurring plant steroid hormones that can induce plant tolerance to various plant stresses by regulating ROS production in cells, but the underlying mechanisms of this scavenging activity by BRs are not well understood. This study investigated the effects of 28-homobrassinolide (28-HBL) seed priming on Brassica juncea seedlings subjected to the combined stress of extreme temperatures (low, 4 °C or high, 44 °C) and salinity (180 mM), either alone or supplemented with 28-HBL treatments (0, 10⁻⁶, 10⁻⁹, 10⁻¹² M). The combined temperature and salt stress treatments significantly reduced shoot and root lengths, but these improved when supplemented with 28-HBL although the response was dose-dependent. The combined stress alone significantly increased H₂O₂ content, but was inhibited when supplemented with 28-HBL. The activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOX), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) increased in response to 28-HBL. Overall, the 28-HBL seed priming treatment improved the plant’s potential to combat the toxic effects imposed by the combined temperature and salt stress by tightly regulating the accumulation of ROS, which was reflected in the improved redox state of antioxidants.

Jasmonic acid-induced tolerance to root-knot nematodes in tomato plants through altered photosynthetic and antioxidative defense mechanisms

Plant parasitic nematodes cause severe damage to cultivated crops globally. Management of nematode population is a major concern as chemicals used as nematicides have negative impact on the environment. Natural plant products can be safely used for the control of nematodes. Among various plant metabolites, plant hormones play an essential role in developmental and physiological processes and also assist the plants to encounter stressful conditions. Keeping this in mind, the present study was designed to evaluate the effect of jasmonic acid (JA) on the growth, pigments, polyphenols, antioxidants, osmolytes, and organic acids under nematode infection in tomato seedlings. It was observed that nematode inoculation reduced the growth of seedlings. Treatment with JA improved root growth (32.79%), total chlorophylls (71.51%), xanthophylls (94.63%), anthocyanins (37.5%), and flavonoids content (21.11%) when compared to inoculated seedlings alone. The JA application enhanced the total antioxidant capacity (lipid- and water-soluble antioxidants) by 38.23 and 34.37%, respectively, in comparison to infected seedlings. Confocal studies revealed that there was higher accumulation of glutathione in hormone-treated seedlings under nematode infection. Treatment with JA increased total polyphenols content (74.56%) in comparison to nematode-infested seedlings. JA-treated seedlings also enhanced osmolyte and organic acid contents under nematode stress. Overall, treatment with JA improved growth, enhanced pigment levels, modulated antioxidant content, and enhanced osmolyte and organic acid content in nematode-infected seedlings.