Warm nights disrupt global transcriptional rhythms in field-grown rice panicles

Abstract

33In rice, a small increase in nighttime temperatures reduces grain yield and quality. How warm nighttime 34 temperatures (WNT) produce these detrimental effects is not well understood, especially in field conditions 35 where the normal day to night temperature fluctuation exceeds the mild increase in nighttime temperature. 36We observed genome-wide disruption of gene expression timing during the reproductive phase on field-37 grown rice panicles acclimated to 2-3°C WNT. Rhythmically expressed transcripts were more sensitive to 38 WNT than non-rhythmic transcripts. The system-wide transcriptional perturbations suggest that WNT 39 disrupts the tight temporal coordination between internal molecular events and the environment resulting 40 in reduced productivity. We identified transcriptional regulators whose predicted targets are enriched for 41 sensitivity to WNT. The affected transcripts and candidate regulators identified through our network 42 analysis explain molecular mechanisms driving sensitivity to WNT and candidates that can be targeted to 43 enhance tolerance to WNT. 44 45 KEYWORDS: climate change impact, global food security, nighttime temperature increase, circadian 46 regulators, diel transcriptional networks, rhythmic expression, rice panicles 47 48 49 101 102 RESULTS 103 WNT NEGATIVELY IMPACT BIOMASS AND YIELD 104 105IR64, a popular high-yielding rice variety, was grown under normal nighttime temperatures (NNT) or under 106 warm nighttime temperatures (WNT), using a field-based infrared ceramic heating system (Fig. S1). WNT 107 treatment started at panicle initiation and continued through maturity. At 50% flowering, field-grown rice 108 panicles were collected for transcriptional analysis throughout the 24h cycle. WNT maintained a 2-3°C

Single cell gene regulatory networks in plants: Opportunities for enhancing climate change stress resilience

“…Moreover, rice flowers have a noted sensitivity to high nighttime temperatures (Desai et al, 2019). Selecting appropriate sampling times will have to consider these various aspects of stress response.…”

“…For developing rice flowers, extensive physiological, agronomic, and anatomical examinations of heat stress responses have identified sensitive developmental stages and tissues (Cheabu, Moung‐Ngam, Arikit, Vanavichit, & Malumpong, 2018 ; Jagadish, Craufurd, & Wheeler, 2007 ). Moreover, rice flowers have a noted sensitivity to high nighttime temperatures (Desai et al, 2019 ). Selecting appropriate sampling times will have to consider these various aspects of stress response.…”

Molecular mapping and characterization of QTLs for grain quality traits in a RIL population of US rice under high nighttime temperature stress

“…However, until now, no study has been reported on QTLs mapping for GL and GW under HNT stress in bi-parental populations in rice worldwide. Despite the increasing knowledge of QTL mapping, metabolomics 65 , and transcriptomic 66 , 67 responses to HNT stress in rice, the understanding and dissection of genetic basis of grain quality traits and HNT stress tolerance in rice is still limited. Hence, based on our best knowledge and recent survey of the literature & databases, in the United States, this is the first study to identify genetic loci and putative candidate genes controlling grain quality traits and HNT stress tolerance mechanisms in tropical japonica (TRJ) rice under HNT stress.…”

Circadian Regulation of the Plant Transcriptome Under Natural Conditions

“…For example, a 1°C increase in the temperature during the night can decrease rice grain yield by 10% (Peng et al, 2004). Furthermore, warm night temperatures disrupt rhythmically expressed genes, particularly those genes driven by thermocyles (Desai et al, 2019), which has impacts upon productivity.…”