The YODA (YDA) kinase pathway is intimately associated with the control of Arabidopsis (Arabidopsis thaliana) embryo development, but little is known regarding its regulators. Using genetic analysis, HEAT SHOCK PROTEIN 90 (HSP90) proteins emerge as potent regulators of YDA in the process of embryo development and patterning. This study is focused on the characterization and quantification of early embryonal traits of single and double hsp90 and yda mutants. HSP90s genetic interactions with YDA affected the downstream signaling pathway to control the development of both basal and apical cell lineage of embryo. Our results demonstrate that the spatiotemporal expression of WUSCHEL-RELATED HOMEOBOX 8 (WOX8) and WOX2 is changed when function of HSP90s or YDA is impaired, suggesting their essential role in the cell fate determination and possible link to auxin signaling during early embryo development. Hence, HSP90s together with YDA signaling cascade affect transcriptional networks shaping the early embryo development.

• MeSH
• Arabidopsis genetics   growth & development   metabolism   MeSH
• Genetic Variation MeSH
• Genotype MeSH
• MAP Kinase Kinase Kinases metabolism   MeSH
• Arabidopsis Proteins genetics   metabolism   MeSH
• HSP90 Heat-Shock Proteins genetics   metabolism   MeSH
• Gene Expression Regulation, Plant MeSH
• Genes, Plant MeSH
• Seeds genetics   growth & development   metabolism   MeSH
• Gene Expression Regulation, Developmental MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• MAP Kinase Kinase Kinases MeSH
• Arabidopsis Proteins MeSH
• HSP90 Heat-Shock Proteins MeSH

Stomatal development is tightly connected with the overall plant growth, while changes in environmental conditions, like elevated temperature, affect negatively stomatal formation. Stomatal ontogenesis follows a well-defined series of cell developmental transitions in the cotyledon and leaf epidermis that finally lead to the production of mature stomata. YODA signaling cascade regulates stomatal development mainly through the phosphorylation and inactivation of SPEECHLESS (SPCH) transcription factor, while HSP90 chaperones have a central role in the regulation of YODA cascade. Here, we report that acute heat stress affects negatively stomatal differentiation, leads to high phosphorylation levels of MPK3 and MPK6, and alters the expression of SPCH and MUTE transcription factors. Genetic depletion of HSP90 leads to decreased stomatal differentiation rates. Thus, HSP90 chaperones safeguard the completion of distinct stomatal differentiation steps depending on these two transcription factors under normal and heat stress conditions.

• Keywords
• Stomata, differentiation, heat shock proteins 90, mitogen-activated protein kinases,
• MeSH
• Arabidopsis genetics   metabolism   MeSH
• Arabidopsis Proteins genetics   metabolism   MeSH
• HSP90 Heat-Shock Proteins metabolism   MeSH
• Plant Stomata metabolism   MeSH
• Heat-Shock Response physiology   MeSH
• Gene Expression Regulation, Plant MeSH
• Signal Transduction genetics   physiology   MeSH
• Basic Helix-Loop-Helix Transcription Factors genetics   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• MUTE protein, Arabidopsis MeSH Browser
• Arabidopsis Proteins MeSH
• HSP90 Heat-Shock Proteins MeSH
• SPEECHLESS protein, Arabidopsis MeSH Browser
• Basic Helix-Loop-Helix Transcription Factors MeSH