Fragkostefanakis Sotirios, Mesihovic Anida, Simm Stefan, Paupière Marine Josephine, Hu Yangjie, Paul Puneet, Mishra Shravan Kumar, Tschiersch Bettina, Theres Klaus, Bovy Arnaud, Schleiff Enrico, Scharf Klaus-Dieter
Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, D-60438 Frankfurt am Main, Germany (S.F., A.M., S.S., Y.H., P.P., S.K.M., E.S., K.-D.S.);Cluster of Excellence Frankfurt, Goethe University, D-60438 Frankfurt am Main, Germany (S.S., E.S.);Plant Breeding, Wageningen University, Wageningen 6708PB, The Netherlands (M.J.P., A.B.);Leibniz Institute of Plant Biochemistry, D-06120 Halle (Saale), Germany (B.T., K.-D.S.);Max Planck Institute for Plant Breeding Research, D-50829 Cologne, Germany (K.T.); andBuchmann Institute for Molecular Life Sciences, Goethe University, D-60438 Frankfurt am Main, Germany (E.S.).
Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, D-60438 Frankfurt am Main, Germany (S.F., A.M., S.S., Y.H., P.P., S.K.M., E.S., K.-D.S.);Cluster of Excellence Frankfurt, Goethe University, D-60438 Frankfurt am Main, Germany (S.S., E.S.);Plant Breeding, Wageningen University, Wageningen 6708PB, The Netherlands (M.J.P., A.B.);Leibniz Institute of Plant Biochemistry, D-06120 Halle (Saale), Germany (B.T., K.-D.S.);Max Planck Institute for Plant Breeding Research, D-50829 Cologne, Germany (K.T.); andBuchmann Institute for Molecular Life Sciences, Goethe University, D-60438 Frankfurt am Main, Germany (E.S.)
Plant Physiol. 2016 Apr;170(4):2461-77. doi: 10.1104/pp.15.01913. Epub 2016 Feb 25.
Male reproductive tissues are more sensitive to heat stress (HS) compared to vegetative tissues, but the basis of this phenomenon is poorly understood. Heat stress transcription factors (Hsfs) regulate the transcriptional changes required for protection from HS In tomato (Solanum lycopersicum), HsfA2 acts as coactivator of HsfA1a and is one of the major Hsfs accumulating in response to elevated temperatures. The contribution of HsfA2 in heat stress response (HSR) and thermotolerance was investigated in different tissues of transgenic tomato plants with suppressed HsfA2 levels (A2AS). Global transcriptome analysis and immunodetection of two major Hsps in vegetative and reproductive tissues showed that HsfA2 regulates subsets of HS-induced genes in a tissue-specific manner. Accumulation of HsfA2 by a moderate HS treatment enhances the capacity of seedlings to cope with a subsequent severe HS, suggesting an important role for HsfA2 in regulating acquired thermotolerance. In pollen, HsfA2 is an important coactivator of HsfA1a during HSR HsfA2 suppression reduces the viability and germination rate of pollen that received the stress during the stages of meiosis and microspore formation but had no effect on more advanced stages. In general, pollen meiocytes and microspores are characterized by increased susceptibility to HS due to their lower capacity to induce a strong HSR This sensitivity is partially mitigated by the developmentally regulated expression of HsfA2 and several HS-responsive genes mediated by HsfA1a under nonstress conditions. Thereby, HsfA2 is an important factor for the priming process that sustains pollen thermotolerance during microsporogenesis.
与营养组织相比，雄性生殖组织对热胁迫（HS）更为敏感，但这一现象的基础尚不清楚。热胁迫转录因子（Hsfs）调节抵御热胁迫所需的转录变化。在番茄（Solanum lycopersicum）中，HsfA2作为HsfA1a的共激活因子，是响应温度升高而积累的主要Hsfs之一。在HsfA2水平受到抑制的转基因番茄植株（A2AS）的不同组织中，研究了HsfA2在热胁迫响应（HSR）和耐热性中的作用。对营养组织和生殖组织中两种主要热休克蛋白（Hsps）的全转录组分析和免疫检测表明，HsfA2以组织特异性方式调节热胁迫诱导基因的子集。适度的热胁迫处理使HsfA2积累，增强了幼苗应对随后严重热胁迫的能力，这表明HsfA2在调节获得性耐热性中起重要作用。在花粉中，HsfA2是热胁迫响应过程中HsfA1a的重要共激活因子。HsfA2的抑制降低了在减数分裂和小孢子形成阶段受到胁迫的花粉的活力和萌发率，但对更后期阶段没有影响。一般来说，花粉母细胞和小孢子对热胁迫的敏感性增加，因为它们诱导强烈热胁迫响应的能力较低。在非胁迫条件下，HsfA2的发育调控表达以及由HsfA1a介导的几个热胁迫响应基因部分缓解了这种敏感性。因此，HsfA2是在小孢子发生过程中维持花粉耐热性的引发过程的重要因素。
