Agriculture and Agri-Food Canada

About: Agriculture and Agri-Food Canada is a facility organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Soil water. The organization has 10921 authors who have published 21332 publications receiving 748193 citations. The organization is also known as: Department of Agriculture and Agri-Food.

HISTONE DEACETYLASE19 Is Involved in Jasmonic Acid and Ethylene Signaling of Pathogen Response in Arabidopsis

Abstract: Histone acetylation is modulated through the action of histone acetyltransferases and deacetylases, which play key roles in the regulation of eukaryotic gene expression. Previously, we have identified a yeast histone deacetylase REDUCED POTASSIUM DEPENDENCY3 (RPD3) homolog, HISTONE DEACETYLASE19 (HDA19) (AtRPD3A), in Arabidopsis thaliana . Here, we report further study of the expression and function of HDA19 . Analysis of Arabidopsis plants containing the HDA19 :β-glucuronidase fusion gene revealed that HDA19 was expressed throughout the life of the plant and in most plant organs examined. In addition, the expression of HDA19 was induced by wounding, the pathogen Alternaria brassicicola , and the plant hormones jasmonic acid and ethylene. Using green fluorescent protein fusion, we demonstrated that HDA19 accumulated in the nuclei of Arabidopsis cells. Overexpression of HDA19 in 35S : HDA19 plants decreased histone acetylation levels, whereas downregulation of HDA19 in HDA19 -RNA interference (RNAi) plants increased histone acetylation levels. In comparison with wild-type plants, 35S : HDA19 transgenic plants had increased expression of ETHYLENE RESPONSE FACTOR1 and were more resistant to the pathogen A. brassicicola . The expression of jasmonic acid and ethylene regulated PATHOGENESIS-RELATED genes, Basic Chitinase and β -1,3-Glucanase , was upregulated in 35S : HDA19 plants but downregulated in HDA19- RNAi plants. Our studies provide evidence that HDA19 may regulate gene expression involved in jasmonic acid and ethylene signaling of pathogen response in Arabidopsis.

Impact of tillage practices on organic carbon and nitrogen storage in cool, humid soils of eastern Canada

Abstract: Soil organic matter storage capacity in agroecosystems varies with soil type, climate and agricultural management practices. The effects of different tillage systems on organic C and N storage were determined for a range of soils of eastern Canada mainly under continuous corn and small grain cereal production. Soil profiles from eight sites on which comparative tillage experiments had been performed for up to 11 years were sampled to a 60 cm depth in four increments (0–10, 10–20, 20–40 and 40–60cm). Organic C and N contents and dry bulk density were determined for each sampling depth. Bulk density measurements showed that the total soil mass in the soil profiles was not influenced by the tillage systems. No significant differences were found between tillage treatments in the total organic C and N storage down to 60 cm depth; the soil profiles under no-till (NT) and chisel plowing (CP) generally did not contain more C and N than those under conventional moldboard plowing (MP). However, the depth distribution of soil C and N varied with tillage. In the surface 0–10cm, C and N contents were higher under NT than under MP, whereas at deeper levels (20–40cm) the reverse trend was observed. It is concluded than under eastern Canadian conditions, where crop production and residue inputs are not affected by tillage, reduced tillage systems would not result in the storage of more soil organic matter in the entire soil profile at least in a 5–10 year period. Placement of the residues would be a major factor influencing the C and N distribution at specific depths.