A Passive Repression Mechanism that Hinders Synergic Transcriptional Activation by Heat Shock Factors Involved in Sunflower Seed Longevity
Dear Editor,
Different genetic programs that are active during late stages of zygotic embryogenesis are involved in seed phenotypes as longevity,basal thermotolerance,and desiccation tolerance.In sunflower,Heat Shock Factor A9 (HaHSFA9) controls one of such programs:the HaHSFA9 program.Overexpression of HaHSFA9 in seeds of transgenic tobacco showed the involvement of this transcription factor in basal thermotolerance and longevity;HaHSFA9 activated a genetic program that includes specific small Heat Shock Protein (sHSP) genes,which are expressed mainly (or exclusively) during zygotic embryogenesis in seeds (Prieto-Dapena et al.,2006).We also used an active-repressor dominant-negative (DN) form of HlaHSFA9,and thus we obtained a substantial reduction of both the accumulation of specific sHSPs and of seed longevity (Tejedor-Cano et al.,2010).In contrast,transcriptioninactive DN forms were inefficient.We therefore inferred the participation of additional HSF(s) in controlling the genetic program activated by HaHSFAg,rather than involvement of a single master control HSF (i.e.HaHSFA9 only).These additional HSF(s) would belong to class A,as HaHSFA9 (Tejedor-Cano et al.,2010).
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the European Regional Development Fund;the Spanish Secretary of Research,Development,and Innovation Grants BIO2008-00634 and BIO2011-23440 to J.J..Additional funds were obtained from the Andalusian Regional GovernmentGrant BIO148 to J.J.
2014-03-20（万方平台首次上网日期，不代表论文的发表时间）
共4页
256-259
