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Zeaxanthin epoxidase (ZEP) plays important roles in plant response to various environmental stresses by involving in abscisic acid (ABA) biosynthesis and xanthophyll cycle. A full-length cDNA of PeZEP was isolated from moso bamboo (Phyllostachys edulis), which comprised of a 138-bp 5¢-untranslated region (UTR), a 381-bp 3¢-UTR, and a 2013-bp open reading frame (ORF) encoding a putative protein of 670 amino acids. PeZEP was mainly expressed in leaf blades and leaf sheaths, and less in roots and culms. The transcript level of PeZEP in bamboo leaf was elevated with the increasing light intensity. PeZEP was significantly upregulated in response to high light (HL: 1200 μmol.m-2.s-1) and reached to a higher level after 1 h treatment, and kept higher levels in the following hours. Besides, PeZEP was upregulated under high temperature (42°C), and downregulated under low temperature (4°C) and exogenous ABA treatment. The expression vector of PeZEP driven by CaMV 35S was constructed and transformed into Arabidopsis thaliana. The transgenic plants overexpressing PeZEP were generated and subjected to drought stress for morphological and physiological assays. Compared with Col-0, the transgenic plants demonstrated enhanced tolerance to drought stress, which appeared later wilting and higher survival rate. Moreover, higher value of Fv/Fm, higher activities of superoxide dismutase, peroxidase, and catalase, and lower concentration of malondialdehyde were also observed in transgenic plants. Transcript levels of AtP5CS and AtRD29b related to drought stress were enhanced in transgenic plants. These results indicated that PeZEP might play an important function in response to drought stress in bamboo. [ABSTRACT FROM AUTHOR]

UDP-galactose-4-epimerase (UGE) is a key enzyme involved in galactose metabolism by catalyzing the interconversion of UDP-glucose to UDP-galactose. The cDNA encoding UGE was isolated from Phyllostachys edulis by reverse transcription-polymerase chain reaction and by 5' and 3' rapid amplification of cDNA ends, and was designated as PeUGE. The full-length cDNA of PeUGE was 1778 bp, which contained an open reading frame (ORF) encoding a peptide of 420 amino acids, with a calculated molecular mass of 46.58 kDa and a theoretic isoelectric point of 9.07. The genomic sequence corresponding to the ORF of PeUGE was 2656 bp containing 10 exons separated by nine introns. Tissue-specific analysis showed that PeUGE was constitutively expressed with the highest level in shoots, which had an increasing trend with the growth of shoots. PeUGE was induced by abiotic stresses such as drought, salinity, and water stresses. Moreover, chlorophyll fluorescence parameters and lateral roots analysis of transgenic Arabidopsis thaliana plants overexpressing PeUGE systematically confirmed the crucial role of PeUGE in improving the tolerance to abiotic stresses. These results indicated that PeUGE might be one of the key genes involved in the biosynthesis of cell wall polysaccharides during the growth and development of bamboo and in response to stresses, which provided a candidate gene for molecular engineering to improve the quality of bamboo products. [ABSTRACT FROM AUTHOR]