In cells, metallochaperones are important proteins that safely transport metal ions. Heavy metal-associated isoprenylated plant proteins (HIPPs) are metallochaperones that contain a metal binding domain and a CaaX isoprenylation motif at the carboxy-terminal end. To investigate the roles of wheat heavy metal-associated isoprenylated plant protein (TaHIPP) genes in plant development and in stress responses, we isolated cDNA encoding the wheat TaHIPP1 gene, which contains a heavy metal-associated domain, nuclear localisation signals and an isoprenylation motif (CaaX motif). Quantitative real-time PCR analysis indicated that the TaHIPP1 gene was differentially expressed under biotic and abiotic stresses. Specifically, TaHIPP1 expression was up-regulated by ABA exposure or wounding. Additionally, TaHIPP1 over-expression in yeast (Schizosaccharomyces pombe) significantly increased the cell growth rate under Cu(2+) and high salinity stresses. The nuclear localisation of the protein was confirmed with confocal laser scanning microscopy of epidermal onion cells after particle bombardment with chimeric TaHIPP1-GFP constructs. In addition, TaHIPP1 was shown to enhance the susceptibility of wheat to Pst as determined by virus-induced gene silencing. These data indicate that TaHIPP1 is an important component in defence signalling pathways and may play a crucial role in the defence response of wheat to biotic and certain abiotic stresses.

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In Meixian County of Shaanxi Province, China, during the summer of 2002, mature corn plants in a field plot showed severe leaf spot symptoms. The lesions were narrow (3.5 to 18 mm long and 0.4 to 1.5 mm wide), grayish tan, and surrounded by a light- to dark-pigmented border. Leaves wilted when lesions coalesced. From 2002 to 2005, the disease was observed in other Shaanxi Province counties, including Yangling, Wugong, Qianxian, Longxian, and Qianyang, although in most cases, symptom development was less severe than it was in Meixian. Seven isolates from four counties were obtained by isolation from host tissue on potato dextrose agar (PDA), followed by single-spore culturing and incubation on PDA at 25°C in the dark for 7 days. Conidial suspensions were prepared from a single-spored culture on PDA plates. Pathogenicity tests were performed by spraying five corn seedlings (cv. Yuyu 22) at the three- to four-leaf stage in separate 10-cm-diameter pots with 10 ml of a conidial suspension (106 spores per ml) per plant. Each of three isolates was used in separate inoculations that were performed in different weeks. Controls were sprayed with sterile distilled water only. Plants were covered with plastic bags for 48 h and incubated at 23 to 25°C in a chamber. One week after inoculation, leaves on all inoculated plants developed characteristic lesions, whereas untreated controls had no symptoms. The pathogen was reisolated from diseased leaves on PDA after surface sterilization with 2% NaOCl. On PDA, proliferation of conidia usually occurred on all sides of the conidiophore. Conidiophores were cylindrical, simple, smooth, septate, and straight to flexuous. Conidia were 49 to 89 μm long and 11 to 17 μm wide, with 3 to 10 distosepta, straight or moderately curved, dark or olivaceous brown, and the cells on the ends sometimes appeared paler than those in the middle. These characteristics match those of Bipolaris zeicola (Stout) Shoemaker. On the basis of the arbitrary primers selected by Jones et al. (1), random amplified polymorphic DNA (RAPD) analysis was used for species and physiological race determination. A single DNA fragment approximately 1.2 kb, which is characteristic of B. zeicola, was amplified from all seven isolates with arbitrary primer A20 (5′CTTGGATTC3′). Analysis of PCR products obtained with arbitrary primer A03 (5′AGTCAGCCAC3′) showed that all seven isolates lacked 2,700- and 2,300-base bands, and therefore, sorted into B. zeicola race 3. On the basis of pathogenicity, morphology, and RAPD band patterns of primer A20, the fungus was confirmed as B. zeicola. The shape of leaf lesions and RAPD band patterns using primer A03 showed further that the pathogen was race 3 of B. zeicola. Bai et al. (2) reported race 1 and race 2 of B. zeicola in China, but to our knowledge, this is the first report of race 3 in China. References: (1) M. J. Jones and L. D. Dunkle. Phytopathology 83:366, 1993. (2) J. K. Bai et al. Acta Phytopathol. Sin. 12:61, 1982.

Very long chain fatty acids (VLCFAs) are essential lipid components in many plants. 3 Ketoacyl CoA synthase (KCS) catalyzes the condensation reaction to form 3 ketoacyl CoA in VLCFA synthesis. AtELO4 has been reported to be involved in VLCFA synthesis, functioning as a KCS in Arabidopsis. However, no stud ies on other three AtELO members have been reported. Here, we initially found by real time PCR in Arabi dopsis thaliana (L.) Heynh. that AtELO1, AtELO3, and AtELO4 displayed characteristic expression patterns, but AtELO2 was nearly expressed in any organ. Then the transient expression of ELO like eGFP fusions in Arabidopsis green leaf protoplasts showed that AtELO1, AtELO3, and AtELO4 were localized in the endo plasmic reticulum (ER), where VLCFA synthesis took place. Finally, we found that the contents of all fatty acids were decreased by 10-20% in seeds of atelo1 T DNA insertion mutants. In seeds of Pro35S:AtELO1 plants, the levels of all remaining components, except C20:0 and C20:3, were significantly increased. Taken together, our study revealed biological functions of AtELO members and might lay the foundation for further genetic manipulations to generate oil crops with the high oil content.