GhHmgB3 deficiency deregulates proliferation and differentiation of cells during somatic embryogenesis in cotton

Abstract

SummaryThe proteins of high-mobility group box (HmgB) family were involved in the regulation of transcription and other DNA-dependent processes. To investigate the function of HmgB proteins during cotton somatic embryogenesis (SE), four Gossypium hirsutum HmgB genes were characterized. The gene GhHmgB3 preferentially expressed in embryonic tissues and was studied in detail. RNA interference and over-expression was used to regulate the expression of GhHmgB3 during cotton SE by transforming both hypocotyl and embryogenic calli (ECs) via Agrobacterium tumefaciens. The GhHmgB3-deficient somatic cells of hypocotyls dedifferentiated more vigorously than the control cells, but they failed to differentiate to ECs. In another case, the proliferation and differentiation of GhHmgB3-deficient ECs were significantly improved, but failed to form plantlets. Over-expression of GhHmgB3 had no significant differences in callus initiation and differentiation compared with the control cell lines. The different expression genes between the control and GhHmgB3-deficient ECs were identified by Solexa sequencing technology. The bioinformatics analysis and experimental verification revealed series of abnormal mechanism associated with b-catenin signalling. These results in response to the down-regulation of GhHmgB3 revealed series of b-catenin-related mechanisms might be responsible for the deregulation of proliferation and differentiation of cells in cotton SE.

Cotton GhCKI disrupts normal male reproduction by delaying tapetum programmed cell death via inactivating starch synthase

“…Bud proteins were extracted in an extraction buffer containing 50 mM Tris/HCl (pH 7.5), 10 mM KCl, 1 mM EDTA, 2 mM dithiothreitol and 0.5 mM phenylmethanesulfonyl fluoride. Western blotting was performed as described previously (Hu et al, 2011b). A casein kinase I assay kit (Sigma, http://www.sigmaaldrich.com/) was used to measure CKI activity.…”

GbPDF1 Is Involved in Cotton Fiber Initiation via the Core cis-Element HDZIP2ATATHB2

“…The proteins were collected from the ovules and fibers in extraction buffer containing 50 mM Tris-HCl (pH 8.0), 0.5 mM CaCl 2 , 0.1% b-mercaptoethanol, 0.5% Triton X-100, and 1 mM phenylmethylsulfonyl fluoride. Western-blot experiments were performed as reported by Hu et al (2011).…”

Plant Proteins Containing High Mobility Group Box DNA-Binding Domains Modulate Different Nuclear Processes

“…Reduced expression of cotton HMGB3 (which is preferentially expressed in embryonic tissue) altered the potential of cells to differentiate and dedifferentiate during somatic embryogenesis. Some of the genes differentially expressed in the HMGB3-deficient cells (versus control cells) were found to encode putative plant components of the pathway that in mammals is involved in b-catenin signaling (Hu et al, 2011). The significance of this interesting finding remains to be clarified.…”