These authors contributed equally to this work. SummaryA key regulated step in abscisic acid (ABA) biosynthesis in plants is catalyzed by 9-cis epoxycarotenoid dioxygenase (NCED), which cleaves 9-cis xanthophylls to xanthoxin, a precursor of ABA. In Arabidopsis, ABA biosynthesis is controlled by a small family of NCED genes. Nine carotenoid cleavage dioxygenase (CCD) genes have been identi®ed in the complete genome sequence. Of these, ®ve AtNCEDs (2, 3, 5, 6, and 9) have been cloned and studied for expression and subcellular localization. Although all ®ve AtNCEDs are targeted to plastids, they differ in binding activity of the thylakoid membrane. AtNCED2, AtNCED3, and AtNCED6 are found in both stroma and thylakoid membrane-bound compartments. AtNCED5 is exclusively bound to thylakoids, whereas AtNCED9 remains soluble in stroma. A quantitative real-time PCR analysis and histochemical staining of promoter::GUS activity in transgenic Arabidopsis revealed a complex pattern of localized NCED expression in well-watered plants during development. AtNCED2 and AtNCED3 account for the NCED activity in roots, with localized expression in root tips, pericycle, and cortex cells at the base of lateral roots. Localized AtNCED2 and AtNCED3 expression in pericycle cells is an early marker of lateral initiation sites. AtNCED5, AtNCED6, AtNCED3, and AtNCED2 are expressed in¯owers with very high AtN-CED6::GUS activity occurring in pollen. AtNCED5::GUS, and to lesser degrees, AtNCED2::GUS and AtN-CED3::GUS are expressed in developing anthers. AtNCED5, AtNCED6, AtNCED9, and AtNCED3 contribute to expression in developing seeds with high levels of AtNCED6 present at an early stage. GUS analysis indicates that AtNCED3 expression is con®ned to the base of the seed, whereas AtNCED5 and AtNCED6 are expressed throughout the seed. Consistent with the studies conducted by Iuchi and his colleagues in 2001, AtNCED3 is the major stress-induced NCED in leaves. Our results indicate that developmental control of ABA synthesis involves localized patterns of AtNCED gene expression. In addition, differential membrane-binding capacity of AtNCEDs is a potential means of post-translational regulation of NCED activity.

Soybean [Glycine max (L.) Merr.] seed contains an immunodominant human allergen P34 or Gly m Bd 30k (mentioned as P34) of the cysteine protease family. of approximately 16 266 accessions from USDA soybean germplasm screened, 12 P34 null lines were identified among soybean (G. max), wild annual (Glycine soja Sieb. and Zucc.), and wild perennial Glycine spp. Glycine soja were low P34 expressers, while G. max and wild perennial species had nondetectable levels of the allergenic protein. Further investigation of G. max nulls by 2D‐IEF/SDS PAGE showed all primary seed proteins present indicating that the loss of P34 was not due to large scale restructuring of protein content. Southern and northern analysis showed no large insertions or deletions to render the gene nonfunctional. The cDNA of both G. max nulls each showed the same six point mutations indicating the two nulls have a single origin. of these six single nucleotide changes, four are predicted to result in an amino acid alteration. One such alteration results in a serine being replaced by a cysteine residue. The introduction of a cysteine residue might produce a mismatched disulfide bond formation producing an unstable P34 protein in the null soybean accessions. The isolation and introgression of soybean lines with low allergen levels will provide the basis for developing a low allergen line incorporated with other agronomically desirable traits in a breeding program.

Many plant mitogen-activated protein kinases (MAPKs) play an important role in regulating responses to both abiotic and biotic stresses. The first reported rice MAPK gene BWMK1 is induced by both rice blast (Magnaporthe grisea) infection and mechanical wounding. For further analysis of its response to other environmental cues and plant hormones, such as jasmonic acid (JA), salicylic acid (SA), and benzothiadiazole (BTH), the promoter of BWMK1 was fused with the coding region of the ß-glucuronidase (GUS) reporter gene. Two promoter-GUS constructs with a 1.0-and 2.5-kb promoter fragment, respectively, were generated and transformed into the japonica rice cultivars TP309 and Zhonghua 11. Expression of GUS was induced in the transgenic lines by cold, drought, dark, and JA. However, light, SA, and BTH treatments suppressed GUS expression. These results demonstrate that BWMK1 is responsive to multiple abiotic stresses and plant hormones and may play a role in cross-talk between different signaling pathways.Key words: abiotic stresses; BWMK1; disease resistance; mitogen-activated protein kinase; Oryza sativa; promoter.Hong WF, He C, Wang L, Wang DJ, Joseph LM, Jantasuriyarat C, Dai L, Wang GL (2007). BWMK1 responds to multiple environmental stresses and plant hormones. J. Integr. Plant Biol. 49(6), 843−851. Available online at www.blackwell-synergy.com/links/toc/jipb, www.jipb.net Because plants have been exposed to a wide range of environmental signals, they have developed sophisticated mechanisms to recognize those signals and integrate them into specific signaling pathways that moderate their output. The series of signal transductions that lead to modification of gene expression patterns allow plants to adapt to changes in their environment throughout their life cycle. Mitogen-activated protein kinase (MAPK) pathways have been reported to be central components of such signal transduction pathways (Hirt 1997;Stratmann and Ryan 1997;Seo et al. 1999; Ichimura et al. 2002). MAPKs are known to respond to a wide variety of different stimuli and to enable transmission of the signal from the receptors/sensors into the cytosol and nucleus (Ligterink et al. 1997; Lenormand et al. 1998; Kyriakis and Avruch 2001;Whitehurst et al. 2002). These signaling pathways generally direct cellular activities ranging from gene expression, mitosis, cell division, cellular differentiation, development, and metabolism to defense responses.All eukaryotic cells possess a set of MAPK cascades. Each of these is preferentially recruited by distinct sets of stimuli, 844 Journal of Integrative Plant Biology Vol. 49 No. 6 2007 thereby allowing cells to respond coordinately to multiple and divergent inputs. Typically, MAPK cascades consist of three kinase modules: (i) MAPK kinase kinase (MEKK); (ii) MAPK kinase (MAPKK); and (iii) MAPK. The MAPKKK enzyme activates an MAPKK by phosphorylating two serine/threonine residues on its activation loop, which, in turn, is responsible for activating both threonine and tyrosine by phosphorylation o...