http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
PDR-type ABC transporter mediates cellular uptake of the phytohormone abscisic acid
Kang, Joohyun,Hwang, Jae-Ung,Lee, Miyoung,Kim, Yu-Young,Assmann, Sarah M.,Martinoia, Enrico,Lee, Youngsook Proceedings of the National Academy of Sciences 2010 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.107 No.5
<P>Abscisic acid (ABA) is a ubiquitous phytohormone involved in many developmental processes and stress responses of plants. ABA moves within the plant, and intracellular receptors for ABA have been recently identified; however, no ABA transporter has been described to date. Here, we report the identification of the ATP-binding cassette (ABC) transporter Arabidopsis thaliana Pleiotropic drug resistance transporter PDR12 (AtPDR12)/ABCG40 as a plasma membrane ABA uptake transporter. Uptake of ABA into yeast and BY2 cells expressing AtABCG40 was increased, whereas ABA uptake into protoplasts of <I>atabcg40</I> plants was decreased compared with control cells. In response to exogenous ABA, the up-regulation of ABA responsive genes was strongly delayed in <I>atabcg40</I> plants, indicating that ABCG40 is necessary for timely responses to ABA. Stomata of loss-of-function <I>atabcg40</I> mutants closed more slowly in response to ABA, resulting in reduced drought tolerance. Our results integrate ABA-dependent signaling and transport processes and open another avenue for the engineering of drought-tolerant plants.</P>
Na, Jong-Kuk,Kim, Jae-Kwang,Kim, Dool-Yi,Assmann, Sarah M. Oxford University Press 2015 Journal of experimental botany Vol.66 No.13
<P>The <I>Arabidopsis thaliana</I> genome encodes three RNA-binding proteins (RBPs), UBP1-associated protein 2a (UBA2a), UBA2b, and UBA2c, that contain two RNA-recognition motif (RRM) domains. They play important roles in wounding response and leaf senescence, and are homologs of <I>Vicia faba</I> abscisic-acid-activated protein kinase-interacting protein 1 (VfAKIP1). The potato (<I>Solanum tuberosum</I>) genome encodes at least seven AKIP1-like RBPs. Here, two potato RBPs have been characterized, StUBA2a/b and StUBA2c, that are homologous to VfAKIP1 and <I>Arabidopsis</I> UBA2s. Transient expression of <I>StUBA2</I>s induced a hypersensitive-like cell death phenotype in tobacco leaves, and an RRM-domain deletion assay of StUBA2s revealed that the first RRM domain is crucial for the phenotype. Unlike overexpression of <I>Arabidopsis UBA2</I>s, constitutive expression of <I>StUBA2a/b</I> in <I>Arabidopsis</I> did not cause growth arrest and lethality at the young seedling stage, but induced early leaf senescence. This phenotype was associated with increased expression of defence- and senescence-associated genes, including pathogen-related genes (<I>PR</I>) and a senescence-associated gene (<I>SAG13</I>), and it was aggravated upon flowering and ultimately resulted in a shortened life cycle. Leaf senescence of <I>StUBA2a/b Arabidopsis</I> plants was enhanced under darkness and was accompanied by H<SUB>2</SUB>O<SUB>2</SUB> accumulation and altered expression of autophagy-associated genes, which likely cause cellular damage and are proximate causes of the early leaf senescence. Expression of salicylic acid signalling and biosynthetic genes was also upregulated in <I>StUBA2a/b</I> plants. Consistent with the localization of UBA2s-GFPs and VfAKIP1-GFP, soluble-modified GFP-StUBA2s localized in the nucleus within nuclear speckles. StUBA2s potentially can be considered for transgenic approaches to induce potato shoot senescence, which is desirable at harvest.</P>