%0 Journal Article
%T HvCKX2 gene silencing by biolistic or Agrobacterium-mediated transformation in barley leads to different phenotypes
%A Wojciech Zalewski
%A Wac£¿aw Orczyk
%A Sebastian Gasparis
%A Anna Nadolska-Orczyk
%J BMC Plant Biology
%D 2012
%I BioMed Central
%R 10.1186/1471-2229-12-206
%X The mean Agrobacterium-mediated transformation efficiency of Golden Promise was 3.47% (¡À2.82). The transcript level of HvCKX2 in segregating progeny of T1 lines was decreased to 34%. The reduction of the transcript in Agrobacterium-derived plants resulted in decreased CKX activity in the developing and developed leaves as well as in 7 DAP (days after pollination) spikes. The final phenotypic effect was increased productivity of T0 plants and T1 lines. Higher productivity was the result of the higher number of seeds and higher grain yield. It was also correlated with the higher 1000 grain weight, increased (by 7.5%) height of the plants and higher (from 0.5 to 2) numbers of spikes.The transformation efficiency of Golden Promise after biolistic transformation was more than twice as low compared to Agrobacterium. The transcript level in segregating progeny of T1 lines was decreased to 24%. Otherwise, the enzyme activity found in the leaves of the lines after biolistic transformation, especially in cv. Golden Promise, was very high, exceeding the relative level of the control lines. These unbalanced ratios of the transcript level and the activity of the CKX enzyme negatively affected kernel germination or anther development and as a consequence setting the seeds. The final phenotypic effect was the decreased productivity of T0 plants and T1 lines obtained via the biolistic silencing of HvCKX2.The phenotypic result, which was higher productivity of silenced lines obtained via Agrobacterium, confirms the hypothesis that spatial and temporal differences in expression contributed to functional differentiation. The applicability of Agrobacterium-mediated transformation for gene silencing of developmentally regulated genes, like HvCKX2, was proven. Otherwise low productivity and disturbances in plant development of biolistic-silenced lines documented the unsuitability of the method. The possible reasons are discussed.CKX genes belong to a small family of genes coding cytokini
%K RNAi silencing
%K HvCKX2
%K Barley
%K Genetic transformation
%K Agrobacterium
%K Microprojectile bombardment
%U http://www.biomedcentral.com/1471-2229/12/206