Disease relevance of RAB18

• The rab18 mRNA accumulates in plants exposed to low temperature, water stress or exogenous ABA but not in plants subjected to heat shock [1].

High impact information on RAB18

• We clearly demonstrate that PLD signaling for proline biosynthesis is similar to RD29A gene expression and different from the abscisic acid-dependent RAB18 gene expression [2].
• At5g06760, LTI30, RD29A, and RAB18 were stimulated by ABA and also specifically expressed in DGPP-treated cells [3].
• The upregulation of two ABA-induced genes (At5g06760, RAB18) and the downregulation of two ABA-repressed genes (AtCLC-A, ACL) are enhanced in the phs1-3 mutant compared with the wild-type [4].
• Moreover, expression of the ABA-induced gene RAB18 was reduced following ACC application [5].
• In a previous study, we demonstrated that the stimulation of phospholipase D (PLD) activity and plasma membrane anion currents by ABA were both required for RAB18 expression in Arabidopsis thaliana suspension cells [6].

Biological context of RAB18

• The expression of a rab-related gene, rab18, is induced by abscisic acid during the cold acclimation process of Arabidopsis thaliana (L.) Heynh [1].

Associations of RAB18 with chemical compounds

• In contrast to these mainly low temperature-induced genes, the expression of rab18 was strongly induced both in water-stressed and ABA-treated plants but was only slightly responsive to cold [7].
• This stress-related accumulation of the rab18 mRNA is markedly decreased in the ABA-synthesis mutant aba-1, the ABA-response mutant abi-1 or in wild-type plants treated with the carotenoid synthesis inhibitor, fluridone [1].
• Furthermore, a Ca(2+) influx and the activation of anion channels are part of the ABA-signaling pathway leading to the specific expression of RAB18 [8].
• By contrast, specific inhibition of K(+) channels by tetraethylammonium or Ba(2+) did not affect RAB18 expression [9].
• Pretreatment of Arabidopsis thaliana suspension cells with impermeant calcium chelator EGTA inhibited the ABA-induced RAB18 gene expression [10].

Regulatory relationships of RAB18

• Expression of ABI3 increased the ABA-induced accumulation of transcripts for several ABA/cold/drought-responsive genes such as RAB18 and LTI78 [11].

Other interactions of RAB18

• The localization of LTI29, ERD14 and RAB18 in stress-treated plants was not restricted to certain tissues or cell types [12].
• LTI30 and COR47 accumulated primarily in response to low temperature, whereas RAB18 was only found in ABA-treated plants and was the only dehydrin in this study that accumulated in dry seeds [12].
• In vegetative tissues, Arabidopsis FsPP2C1 transgenic plants show ABA-resistant early root growth and diminished induction of the ABA-response genes RAB18 and KIN2, but no effect on stomatal closure regulation [13].
• The expression of the ABA responsive genes, ABI2, rd29B and rab18, was decreased in the 35S:AtERF4-GFP transgenic plants [14].
• Effects of phosphate deficiency and sugars on expression of rab18 in Arabidopsis: hexokinase-dependent and okadaic acid-sensitive transduction of the sugar signal [15].

Analytical, diagnostic and therapeutic context of RAB18

• Consistent with this finding we demonstrate in northern blot experiments that the ABA-responsive gene RAB18 is hyperinduced by ABA in transgenic overexpressor lines as compared to the wild type [16].

References