转录因子 MYB10 的过硫化作用抑制了红皮梨中的花色素苷合成。
Persulfidation of transcription factor MYB10 inhibits anthocyanin synthesis in red-skinned pear.
机构信息
School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China.
Shandong Institute of Pomology, Tai'an 271000, China.
出版信息
Plant Physiol. 2023 Jul 3;192(3):2185-2202. doi: 10.1093/plphys/kiad100.
Hydrogen sulfide (H2S) is a gaseous signaling molecule that delays color change during fruit ripening. Whether H2S affects anthocyanin biosynthesis in red-skinned pears (Pyrus L.) remains unclear. Here, we found that H2S substantially inhibits anthocyanin accumulation in red-skinned pears and the expression of several genes encoding transcription factors is affected in response to H2S signaling. For example, PyMYB10 and PyMYB73 were down-regulated, whereas PyMYB114 and PyMYB6 were up-regulated. Bioinformatics analysis showed that PyMYB73 and PyMYB6, each containing an EAR motif, may negatively regulate anthocyanin accumulation. Transient expression analysis showed that PyMYB73 substantially promotes anthocyanin biosynthesis by co-transforming with PyMYB10/PyMYB114 + PybHLH3; however, PyMYB6 inhibited anthocyanin biosynthesis in strawberry (Fragaria vesca) receptacles and pear fruits, and PyMYB73 interacted with PyMYB10 and PyMYB6 but not PyMYB114 or PybHLH3. Further investigation showed that Cys194 and Cys218 of PyMYB10 were modified by persulfidation and that PyMYB10Cys218Ala substantially increased anthocyanin accumulation by a transient transformation system. Co-transformation of PyMYB10Cys218Ala + PyMYB73/PyMYB6 also promoted anthocyanin accumulation in pear fruits. Yeast two-hybrid assays showed that the mutation of PyMYB10 did not affect the interaction between PyMYB10 and PyMYB73, but it inhibited interaction with PyMYB6. Moreover, H2S weakened the interaction between PyMYB10 and PyMYB73 but enhanced the interaction with PyMYB6. Thus, we provided a model in which PyMYB10 undergoes persulfidation at Cys218, enhancing the interaction with PyMYB6 and reducing the interaction with PyMYB73. These subsequently results in lower expression of the anthocyanin biosynthesis-related genes Pyrus dihydroflavonol 4-reductase (PyDFR), Pyrus anthocyanidin synthase (PyANS), Pyrus UDP-glucose: flavonoid 3-glucosyl transferase (PyUFGT) and Pyrus glutathione S-transferase (PyGST), thereby inhibiting anthocyanin accumulation in red-skinned pears. Our findings provided a molecular mechanism for H2S-mediated anthocyanin biosynthesis in red-skinned pears.
硫化氢（H2S）是一种气态信号分子，可延缓果实成熟过程中的颜色变化。H2S 是否影响红皮梨（Pyrus L.）中的花青苷生物合成尚不清楚。在这里，我们发现 H2S 可显著抑制红皮梨中的花青苷积累，并且响应 H2S 信号，几种编码转录因子的基因的表达受到影响。例如，PyMYB10 和 PyMYB73 下调，而 PyMYB114 和 PyMYB6 上调。生物信息学分析表明，每个都含有 EAR 基序的 PyMYB73 和 PyMYB6 可能负调控花青苷积累。瞬时表达分析表明，PyMYB73 通过与 PyMYB10/PyMYB114+PybHLH3 共转化，可显著促进花青苷生物合成；然而，PyMYB6 抑制草莓（Fragaria vesca）花托和梨果实中的花青苷生物合成，并且 PyMYB73 与 PyMYB10 和 PyMYB6 相互作用，但不与 PyMYB114 或 PybHLH3 相互作用。进一步的研究表明，PyMYB10 的 Cys194 和 Cys218 被过硫化修饰，并且通过瞬时转化系统，PyMYB10Cys218Ala 大量增加花青苷积累。PyMYB10Cys218Ala+PyMYB73/PyMYB6 的共转化也促进了梨果实中的花青苷积累。酵母双杂交试验表明，PyMYB10 的突变不影响 PyMYB10 与 PyMYB73 之间的相互作用，但它抑制了与 PyMYB6 的相互作用。此外，H2S 减弱了 PyMYB10 与 PyMYB73 之间的相互作用，但增强了与 PyMYB6 的相互作用。因此，我们提供了一个模型，即 PyMYB10 在 Cys218 处发生过硫化修饰，增强了与 PyMYB6 的相互作用，降低了与 PyMYB73 的相互作用。这随后导致与花青苷生物合成相关的基因 Pyrus dihydroflavonol 4-reductase（PyDFR）、Pyrus anthocyanidin synthase（PyANS）、Pyrus UDP-glucose:flavonoid 3-glucosyl transferase（PyUFGT）和 Pyrus glutathione S-transferase（PyGST）的表达降低，从而抑制红皮梨中的花青苷积累。我们的发现为 H2S 介导的红皮梨中花青苷生物合成提供了一个分子机制。
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