TRANSCRIPTOMICS OF DEVELOPING MERISTEMS UNDER TERMINAL HEAT STRESS IN CONTRASTING CULTIVARS OF BARLEY (Hordeum Vulgare L.)

Abstract

Global climate change is a multifaceted output of various forms and combinations: Increasing temperature, drought, uneven rain patterns, fluctuations in precipitations, landslides, alarming levels of greenhouse gases, rising sea levels, etc. Global climate change is an alarming concern now throughout the globe; it has already started showing its effects on habitats, which is noticeable worldwide. The decline in ecosystems, ecogeographical biological neiches, and reductions in agricultural productivity is already becoming evident. Indian sub-continent is no exception to global climate change. Indian climatic zone is primarily temperate, combining varied climatic zones and warmer. Its effects have been studied in the Indian subcontinent as well; a steep decline in the Indian economy due to global climate change and a 15 - 17 percent reduction in crop yields are expected. Increasing temperatures are the principal effects of global climate change, causing more severe damage to agricultural productivity, especially cereal crops. Barley is among the dominant staple foods and cereal crops produced worldwide and utilized for multiple purposes; a model crop in monocot species is highly vulnerable to increasing temperatures. Terminal heat stress extremely and negatively impacts the plant development of barley cultivars, reducing both quantity and quality of yield. Therefore, it is crucial to identify genotypes which are resistant to terminal heat stress by observing the critical stages of phenology, and yield determining traits responsible in deciding fate of final crop yield in cultivars exposed to increasing ambient temperatures under heat stress. Growth and development of meristem in barley is a result of complex regulatory networks and well-coordinated transcriptional reprogramming modulated by hormonal, photoperiod, nutrient availability and genetic makeup of cultivars. A critical double ridge stage attained by meristems during phase transitions of vegetative meristems to inflorescence meristem has a significant role in developing the number of spikelets and seeds in lateral stages of plant growth and final crop yield. The early development of meristems leads to attaining early critical stages of phenology and plant growth, completing plant ontogeny in a shorter time displays a heat escaping mechanism to avoid the effects of terminal heat stress on crop growth and yield.