Despite the completion of the Arabidopsis genome sequence, for only a relatively low percentage of the encoded proteins experimental evidence concerning their function is available. Plant proteins that harbour a single PLAT (Polycystin, Lipoxygenase, Alpha-toxin and Triacylglycerol lipase) domain and belong to the PLAT-plant-stress protein family are ubiquitously present in monocot and dicots. However, the function of PLAT-plant-stress proteins is still poorly understood. Therefore, we have assessed the function of the uncharacterised Arabidopsis PLAT-plant-stress family members through a combination of functional genetic and physiological approaches. PLAT1 overexpression conferred increased abiotic stress tolerance, including cold, drought and salt stress, while loss-of-function resulted in opposite effects on abiotic stress tolerance. Strikingly, PLAT1 promoted growth under non-stressed conditions. Abiotic stress treatments induced PLAT1 expression and caused expansion of its expression domain. The ABF/ABRE transcription factors, which are positive mediators of abscisic acid signalling, activate PLAT1 promoter activity in transactivation assays and directly bind to the ABRE elements located in this promoter in electrophoretic mobility shift assays. This suggests that PLAT1 represents a novel downstream target of the abscisic acid signalling pathway. Thus, we showed that PLAT1 critically functions as positive regulator of abiotic stress tolerance, but also is involved in regulating plant growth, and thereby assigned a function to this previously uncharacterised PLAT domain protein. The functional data obtained for PLAT1 support that PLAT-plant-stress proteins in general could be promising targets for improving abiotic stress tolerance without yield penalty.

• MeSH
• aktivace transkripce MeSH
• Arabidopsis klasifikace   růst a vývoj   metabolismus   MeSH
• fylogeneze MeSH
• fyziologický stres * MeSH
• kyselina abscisová farmakologie   MeSH
• nízká teplota MeSH
• období sucha MeSH
• promotorové oblasti (genetika) MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• regulace genové exprese u rostlin účinky léků   MeSH
• retardační test MeSH
• signální transdukce účinky léků   MeSH
• soli chemie   farmakologie   MeSH
• stres endoplazmatického retikula účinky léků   MeSH
• transkripční faktory bZIP genetika   metabolismus   MeSH
• tunikamycin toxicita   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyselina abscisová MeSH
• proteiny huseníčku MeSH
• soli MeSH
• transkripční faktory bZIP MeSH
• tunikamycin MeSH

Sexual plant reproduction depends on the production and differentiation of functional gametes by the haploid gametophyte generation. Currently, we have a limited understanding of the regulatory mechanisms that have evolved to specify the gametophytic developmental programs. To unravel such mechanisms, it is necessary to identify transcription factors (TF) that are part of such haploid regulatory networks. Here we focus on bZIP TFs that have critical roles in plants, animals and other kingdoms. We report the functional characterization of Arabidopsis thaliana AtbZIP34 that is expressed in both gametophytic and surrounding sporophytic tissues during flower development. T-DNA insertion mutants in AtbZIP34 show pollen morphological defects that result in reduced pollen germination efficiency and slower pollen tube growth both in vitro and in vivo. Light and fluorescence microscopy revealed misshapen and misplaced nuclei with large lipid inclusions in the cytoplasm of atbzip34 pollen. Scanning and transmission electron microscopy revealed defects in exine shape and micropatterning and a reduced endomembrane system. Several lines of evidence, including the AtbZIP34 expression pattern and the phenotypic defects observed, suggest a complex role in male reproductive development that involves a sporophytic role in exine patterning, and a sporophytic and/or gametophytic mode of action of AtbZIP34 in several metabolic pathways, namely regulation of lipid metabolism and/or cellular transport.

• MeSH
• Arabidopsis genetika   metabolismus   MeSH
• buněčná stěna metabolismus   ultrastruktura   MeSH
• fluorescenční mikroskopie MeSH
• geneticky modifikované rostliny MeSH
• květy genetika   růst a vývoj   metabolismus   MeSH
• metabolické sítě a dráhy genetika   fyziologie   MeSH
• mikroskopie elektronová rastrovací MeSH
• mutace MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proteiny huseníčku genetika   fyziologie   MeSH
• pyl genetika   metabolismus   ultrastruktura   MeSH
• pylová láčka genetika   růst a vývoj   metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• stanovení celkové genové exprese MeSH
• testy genetické komplementace MeSH
• trans-aktivátory genetika   fyziologie   MeSH
• transmisní elektronová mikroskopie MeSH
• vývojová regulace genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bZIP34 protein, Arabidopsis MeSH Prohlížeč
• proteiny huseníčku MeSH
• trans-aktivátory MeSH