Allelic variation in rice <i>Fertilization Independent Endosperm 1</i> contributes to grain width under high night temperature stress

High night temperature (HNT) causes substantial yield loss in rice (Oryza sativa L.). In this study, the physiological processes related to flag leaf dark respiration (Rn) and grain filling under HNT were explored in a multi‐parent advanced generation intercross population developed for heat tolerance (MAGICheat) along with selected high temperature tolerant breeding lines developed with heat‐tolerant parents. Within a subset of lines, flag leaf Rn under HNT treatment was related to lower spikelet number per panicle and thus reduced yield. HNT enhanced the nighttime reduction of non‐structural carbohydrates (NSC) in stem tissue, but not in leaves, and stem nighttime NSC reduction was negatively correlated with yield. Between heading and harvest, the major difference in NSC concentration was found for starch, but not for soluble sugar. HNT weakened the relationship between NSC remobilization and harvest index at both the phenotypic and genetic level. By using genome‐wide association studies, an invertase inhibitor, MADS box transcription factors and a UDP‐glycosyltransferase that were identified as candidate genes orchestrating stem NSC remobilization in the control treatment were lost under HNT. With the identification of physiological and genetic components related to rice HNT response, this study offers promising prebreeding materials and trait targets to sustain yield stability under climate change.

Section: Discussionmentioning

confidence: 99%

What happens at night? Physiological mechanisms related to maintaining grain yield under high night temperature in rice

Misra

Sreenivasulu

et al. 2021

“…Recently, a clear evidence for a positive role of the locus Fertilization Independent Endosperm ( Fie1 ), a component of the Polycomb Repressive Complex 2 (FIS‐PRC2) complex, for mature grain size under HNT was reported identified by genome‐wide association studies and by testing overexpression lines and knockout mutants (Dhatt et al, 2021).…”

Section: Molecular Responses To Hntmentioning

confidence: 99%

Physiological and molecular attributes contribute to high night temperature tolerance in cereals

Schaarschmidt

Lawas

Kopka

et al. 2021

Asymmetric warming resulting in a faster increase in night compared to day temperatures affects crop yields negatively. Physiological characterization and agronomic findings have been complemented more recently by molecular biology approaches including transcriptomic, proteomic, metabolomic and lipidomic investigations in crops exposed to high night temperature (HNT) conditions. Nevertheless, the understanding of the underlying mechanisms causing yield decline under HNT is still limited. The discovery of significant differences between HNT‐tolerant and HNT‐sensitive cultivars is one of the main research directions to secure continuous food supply under the challenge of increasing climate change. With this review, we provide a summary of current knowledge on the physiological and molecular basis of contrasting HNT tolerance in rice and wheat cultivars. Requirements for HNT tolerance and the special adaptation strategies of the HNT‐tolerant rice cultivar Nagina‐22 (N22) are discussed. Putative metabolite markers for HNT tolerance useful for marker‐assisted breeding are suggested, together with future research directions aimed at improving food security under HNT conditions.

“…In embryo: AC, axial cell; BC, basal cell; COL, coleoptile; EP, embryo proper; P1, leaf stage 1; RAM, root apical meristem; SU, suspensor; SCU, scutellum; SAM, shoot apical meristem. Crops and heat stress references: rice—[1] (Chen et al, 2016); [2] (Dhatt et al, 2020); [3] (Folsom, Begcy, Hao, Wang, & Walia, 2014); [4] (Paul et al, 2020); [5] (Begcy, Sandhu, & Walia, 2018); tomato—[6] (Iwahori, 1966); bush bean—[7] (Ormrod, Woolley, Eaton, & Stobbe, 1967) [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Post‐fertilization and Early Embryogenesismentioning

confidence: 99%

Section: Post‐fertilization and Early Embryogenesismentioning

confidence: 99%

“…A recent study analysed early grain development (1–10 days after fertilization) in rice subjected to high night temperature (28°C) that generally affects rice grain chalkiness (Dhatt et al, 2020). This study further identified FIE1 as a key regulator of grain width since knockout mutants recorded decreased grain size under high night temperature (Dhatt et al, 2020). Moreover, the FIE1 was shown to be pleiotropically involved in rice grain chalk formation as reduced FIE1 recorded a significant increase in grain chalkiness under heat stress, attributed to abnormal starch packing (Dhatt et al, 2020).…”

Section: Post‐fertilization and Early Embryogenesismentioning

confidence: 99%

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The neglected other half ‐ role of the pistil in plant heat stress responses

Wang

Impa

Sunkar

et al. 2021

Heat stress coinciding with reproductive stage leads to a significant loss in reproductive organs viability, resulting in lower seed‐set and crop productivity. Successful fertilization and seed formation are determined by the viability of male and female reproductive organs. The impact of heat stress on the male reproductive organ (pollen) is studied more often compared to the female reproductive organ (pistil). This is attributed to easier accessibility of the pollen coupled with the notion that the pistil's role in fertilization and seed‐set under heat stress is negligible. However, depending on species and developmental stages, recent studies reveal varying degrees of sensitivity of the pistil to heat stress. Remarkably, in some cases, the vulnerability of the pistil is even greater than the pollen. This article summarizes the current knowledge of the impact of heat stress on three critical stages of pistil for successful seed‐set, that is, female reproductive organ development (gametogenesis), pollen‐pistil interactions including pollen capture on stigma and pollen tube growth in style, as well as fertilization and early embryogenesis. Further, future research directions are suggested to unravel molecular basis of heat stress tolerance in pistil, which is critical for sustaining crop yields under predicted warming scenarios.