Key message We describe here the recent developments about the involvement of diverse stress-related proteins in sensing, signaling, and defending the cells in plants in response to drought or/and heat stress. Abstract In the current era of global climate drift, plant growth and productivity are often limited by various environmental stresses, especially drought and heat. Adaptation to abiotic stress is a multigenic process involving maintenance of homeostasis for proper survival under adverse environment. It has been widely observed that a series of proteins respond to heat and drought conditions at both transcriptional and translational levels. The proteins are involved in various signaling events, act as key transcriptional activators and saviors of plants under extreme environments. A detailed insight about the functional aspects of diverse stress-responsive proteins may assist in unraveling various stress resilience mechanisms in plants. Furthermore, by identifying the metabolic proteins associated with drought and heat tolerance, tolerant varieties can be produced through transgenic/recombinant technologies. A large number of regulatory and functional stress-associated proteins are reported to participate in response to heat and drought stresses, such as protein kinases, phosphatases, transcription factors, and late embryogenesis abundant proteins, dehydrins, osmotins, and heat shock proteins, which may be similar or unique to stress treatments. Few studies have revealed that cellular response to combined drought and heat stresses is distinctive, compared to their individual treatments. In this review, we would mainly focus on the new developments about various stress sensors and receptors, transcription factors, chaperones, and stress-associated proteins involved in drought or/ and heat stresses, and their possible role in augmenting stress tolerance in crops.

Climate change, malnutrition, and food insecurity are the inevitable challenges being faced by the agriculture sector today. Plants are susceptible to extreme temperatures during the crucial phases of flowering and seed development, and elevated carbon levels also lead to yield losses. Productivity is also affected by floods and droughts. Therefore, increasing plant yield and stress tolerance are the priorities to be met through novel biotechnological interventions. The contributions of NAC genes towards enhancing plant survivability under stress is well known. Here we focus on the potential of NAC genes in the regulation of abiotic stress tolerance, secondary cell wall synthesis, lateral root development, yield potential, seed size and biomass, ROS signaling, leaf senescence, and programmed cell death. Once naturally tolerant candidate NAC genes have been identified, and the nature of their association with growth and fitness against multi-environmental stresses has been determined, they can be exploited for building inherent tolerance in future crops via transgenic technologies. An update on the latest developments is provided in this review, which summarizes the current understanding of the roles of NAC in the establishment of various stress-adaptive mechanisms in model and food crop plants.

Tea [Camellia sinensis (L.) O. Kuntze] is a perennial tree which undergoes winter dormancy and unlike deciduous trees, the species does not shed its leaves during winters. The present work dissected the molecular processes operating in the leaves during the period of active growth and winter dormancy through transcriptome analysis to understand a long-standing question: why should tea be a non-deciduous species? Analyses of 24,700 unigenes obtained from 57,767 primarily assembled transcripts showed (i) operation of mechanisms of winter tolerance, (ii) down-regulation of genes involved in growth, development, protein synthesis and cell division, and (iii) inhibition of leaf abscission due to modulation of senescence related processes during winter dormancy in tea. These senescence related processes exhibited modulation to favour leaf abscission (i) in deciduous Populus tremula during winters, and (ii) also in tea but under osmotic stress during which leaves also abscise. These results validated the relevance of the identified senescence related processes for leaf abscission and suggested their operation when in need in tea.

Beyond the most crucial roles of RNA molecules as a messenger, ribosomal, and transfer RNAs, the regulatory role of many non-coding RNAs (ncRNAs) in plant biology has been recognized. ncRNAs act as riboregulators by recognizing specific nucleic acid targets through homologous sequence interactions to regulate plant growth, development, and stress responses. Regulatory ncRNAs, ranging from small to long ncRNAs (lncRNAs), exert their control over a vast array of biological processes. Based on the mode of biogenesis and their function, ncRNAs evolved into different forms that include microRNAs (miRNAs), small interfering RNAs (siRNAs), miRNA variants (isomiRs), lncRNAs, circular RNAs (circRNAs), and derived ncRNAs. This article explains the different classes of ncRNAs and their role in plant development and stress responses. Furthermore, the applications of regulatory ncRNAs in crop improvement, targeting agriculturally important traits, have been discussed.

Sorghum downy mildew (SDM), caused by Peronosclerospora sorghi Weston and Uppal (Shaw), is a serious disease of sorghum [Sorghum bicolor (L.) Moench] and maize (Zea mays L.). The wild relatives of sorghum, both cross compatible and cross incompatible with S. bicolor, could provide alternate sources of resistance genes for the long‐term control of SDM. The objective of this study was to assess the downy mildew reaction of several taxa of wild and weedy sorghums. One hundred three wild and weedy sorghums, and six cultivated types belonging to five sections, representing 17 species, originating from Asia, Australia, Africa, and the USA, were greenhouse tested for downy mildew resistance during the rainy seasons of 1998 and 1999 at ICRISAT, Patancheru, India. Forty‐five accessions comprising 15 species from four sections, parasorghum, heterosorghum (S. laxiflorum Bailey), chaetosorghum (S. macrospermum Garber), and stiposorghum (S. angustum S. T. Blake, S. ecarinatum Lazarides, S. extans Lazarides, S. intrans F. Muell. ex Benth., S. interjectum Lazarides, S. stipoideum (Ewart & Jean White) C. Gardener & C. E. Hubb.), including all accessions from Australia, exhibited immunity to downy mildew. Cultivated types and wild races of section Sorghum showed the greatest susceptibility (mean downy mildew infection of 62 and 46%, respectively), while accessions of S. halepense (L.) Pers. were comparatively less susceptible (36% mean downy mildew infection). Potential new sources of resistance genes from wild and weedy sorghums were identified that could be used to develop resistant cultivars to control downy mildew.