Genes encoding chitinase-antifreeze proteins are regulated by cold and expressed by all cell types in winter rye shoots
ABSTRACT One group of antifreeze proteins (AFPs) is composed of two chitinases that accumulate in the apoplast of winter rye leaves during cold acclimation. In this study, the 28- and 35-kDa chitinase-AFPs were localized in nonacclimated and cold-acclimated rye leaves by immunoelectron microscopy with an antiserum produced against the purified winter rye 35-kDa chitinase-AFP. In cold-acclimated winter rye leaves, labelled chitinase-AFPs were abundant in the walls of epidermal, parenchymal sheath and mesophyll cells and xylem vessels, while less label was present in walls of vascular parenchyma cells. In contrast, chitinase labelling was essentially absent in the nonacclimated cells except in xylem vessels. As shown by RNA blotting, the transcripts of chitinase-AFPs accumulated to a high level in rye leaves during cold acclimation, to a lesser extent in crowns and were not detectable in roots. mRNA transcripts of the 28-kDa chitinase-AFP were localized in rye leaves by in situ hybridization. The chitinase-AFP transcripts were found in the same cell types as the protein itself. We conclude that all metabolically active cell types in cold-acclimated winter rye leaves and crowns are able to synthesize chitinase-AFPs and secrete them into adjacent cell walls, where they may interact with ice to delay its propagation through the plant and modify its growth.
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ABSTRACT: In this study, a full-length complementary deoxyribunucleic acid (cDNA) of a fatty acyl–acyl carrier protein thioesterase (CpFATB) was isolated from a Chimonanthus praecox (wintersweet) cDNA library. Wintersweet is a hardy shrub native to Chinese montane regions and is known to be tolerant to many biotic and abiotic stresses including cold, drought, and a variety of plant pathogens. The cDNA is 1,110 nucleotides in length, of which 1,107 bp form a single open-reading frame, predicting a 369 amino acid polypeptide. The deduced amino acid sequence of CpFATB displayed high homology to choroplastic palmitoyl–acyl carrier protein thioesterases from other plants. This gene was subsequently overexpressed in Nicotiana tobaccum using Agrobacterium tumefaciens-mediated transformation. Transcripts of CpFATB were shown to be abundant in leaves of the transformants, but were less highly expressed in roots and least highly expressed in stem tissues. Analysis of the fatty acid composition of transformant leaf tissue showed that the levels of myristic acid (C14:0) in leaf material of transgenic plants was increased by 46% compared with levels observed in wild-type plants. In addition, the level of oleate (C18:1) was reduced by 35%. Of most interest, was the observation that the transformants displayed a far higher degree of drought tolerance than wild type. These data suggest that the CpFATB product may be of utility in the production of transgenic, drought-tolerant crop species.Plant Molecular Biology Reporter 04/2011; 30(2). DOI:10.1007/s11105-011-0359-5 · 2.37 Impact Factor
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ABSTRACT: Low temperatures cause severe damage to none cold hardy grapevines. A preliminary survey with Solexa sequencing technology was used to analyze gene expression profiles of cold hardy Vitis amurensis 'Zuoshan-1' after cold acclimation at 4 °C for 48 h. A total of 16,750 and 18,068 putative genes were annotated for 4 °C-treated and control library, respectively. Among them, 393 genes were upregulated for at least 20-fold, while 69 genes were downregulated for at least 20-fold under the 4 °C treatment for 48 h. A subset of 101 genes from this survey was investigated further using reverse transcription polymerase chain reaction (RT-PCR). Genes associated with signaling events in pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI), including generation of calcium signals (CNGC, CMLs), jasmonic acid signal (JAZ1), oxidative burst (Rboh), and phosphorylation (FLS2, BAK, MEKK1, MKKs) cascades, were upregulated after cold acclimation. Disease resistance genes (RPM1, RPS5, RIN4, PBS1) in the process of effector-triggered immunity (ETI) were also upregulated in the current condition. Defense-related genes (WRKYs, PR1, MIN7) involved in both PTI and ETI processes were abundantly expressed after cold acclimation. Our results indicated that plant-pathogen interaction pathways were linked to the cold acclimation in V. amurensis grapevine. Other biotic- and abiotic-related genes, such as defense (protein phosphatase 2C, U-box domain proteins, NCED1, stilbene synthase), transcription (DREBs, MYBs, ERFs, ZFPs), signal transduction (kinase, calcium, and auxin signaling), transport (ATP-binding cassette (ABC) transporters, auxin:hydrogen symporter), and various metabolism, were also abundantly expressed in the cold acclimation of V. Amurensis 'Zuoshan-1' grapevine. This study revealed a series of critical genes and pathways to delineate important biological processes affected by low temperature in 'Zuoshan-1'.Functional and Integrative Genomics 08/2014; DOI:10.1007/s10142-014-0392-1 · 2.69 Impact Factor
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ABSTRACT: The accumulation of pathogenesis-related proteins such as β-1,3-glucanases and chitinases was studied in cold induced snow mould resistance in two Polish cultivars of winter triticale, cv. Hewo and cv. Magnat that substantially differ in resistance to Microdochium nivale. The plants were pre-hardened at 12°C for 10 days and hardened at 4°C for 28 days. Subsequently, cold hardened plants were inoculated with fungal mycelium (M. nivale) and incubated at 4°C for 7 days in dark. Cold acclimatisation resulted in suppression of the total glucanase and chitinases activities in the resistant Hewo as well as sensitive Magnat cultivars that possibly coincides with altered metabolism. However, upon infection with M. nivale the chitinases were markedly induced in the cv. Hewo. At the same time, total β-1,3 glucanases activities did not seem to be affected by fungus in any of the tested triticale cultivars. The pattern and/or the activity of chitinases in plants might be indicative for the resistance/susceptibility against M. nivale.Biologia 04/2013; 68(2). DOI:10.2478/s11756-013-0001-0 · 0.70 Impact Factor