Modulation of CycD3;1‐CDK complexes by phytohormones and sucrose during maize germination

Abstract

Maize CycD3;1 associates to CDKA or CDKB1;1 proteins during germination and the complexes formed develop kinase activity. These complexes appear to vary in size as germination proceeds, suggesting association to different sets of proteins. CycD3;1 and associated CDK proteins respond to phytohormones and sucrose. Results revealed a reduction in the CycD3;1 protein amount along germination in the presence of indoleacetic acid (IAA) or abscisic acid (ABA), although in the latter protein levels recover at the end of germination. While the levels of CDKA increase with IAA, they decrease with ABA. Both phytohormones, IAA and ABA, increase levels of CDKB1;1 only during the early germination times. CycD3;1 associated kinase activity is only reduced by both phytohormones towards the end of the germination period. On the other hand, lack of sucrose in the imbibition medium strongly reduces CycD3;1 protein levels without affecting the levels of neither CDKA nor CDKB1;1. The corresponding CycD3;1 associated kinase activity is also severely decreased. The presence of sucrose in the medium appears to stabilize the CycD3;1 protein levels.

Morphological Characterization of Flower Buds Development and Related Gene Expression Profiling at Bud Break Stage in Heterodichogamous Cyclocarya paliurus (Batal.) lljinskaja

“…Most genes associated with photoperiod pathway (cryptochrome circadian regulator 2 ( CpCRY2 ) [40], early flowering ( CpELF ), timing of CAB expression 1 ( CpTOC1 )) [42] and vernalization pathway (flower lucos C ( CpFLC ) and flower lucos D ( CpFLD )) [43] were assigned to level III. Level IV, the highest expression contained 2 genes (hexokinase ( CpHXK ) [44] and pyruvate kinase ( CpPK )) [45] belonging to metabolism of glucose, 3 genes responding to GA ( CpDELLA ) [46], CK (cyclin D3 ( CpCYCD3 )) [47], and IAA (auxin responsive GH3 gene family ( CpGH3 )) [38], respectively. Particularly, the expression of CpDEFICIENS [48] in later flowering type was much higher than that in first flowering type.…”

Transcriptome analysis of the genes regulating phytohormone and cellular patterning in Lagerstroemia plant architecture

“…Sablowski and Dornelas (2014) reported that mitotic cycles regulate the cell number in plant tissues, and cytoplasmic growth and cell-wall extension are two determinants that affect the cell volume 36 . The D-type cyclin (CYCD) genes are key cell cycle regulators responsible for triggering G1 to S and G2 to M transitions 37 . Twenty-one unigenes were annotated as CYCD in the Lagerstroemia transcriptome.…”

Roles of plant retinoblastoma protein: cell cycle and beyond

“…Activation of cell cycle gene expression occurs through an increase in CDK/cyclin activity leading to phosphorylation‐dependent inactivation of RBR1's repressor function. This transition has been well studied during maize germination, where changes in the levels of a complex set of D‐type cyclins and KRPs are crucial to control CDK activity (Garza‐Aguilar et al , ; Godínez‐Palma et al , ). D‐type cyclins directly affect RBR1 phosphorylation levels and the release of E2F activity on target genes required to establish active cell proliferation and to initiate vegetative growth (Sánchez‐Camargo et al , ).…”