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The GRAS proteins belong to a plant transcriptional regulator family that function in the regulation of plant growth and development. Despite their important roles, in sunflower only one GRAS gene ( HaDella1) with the DELLA domain has been reported. Here, we provide a functional characterisation of a GRAS-like gene from Helianthus annuus ( Ha- GRASL) lacking the DELLA motif. The Ha- GRASL gene contains an intronless open reading frame of 1,743 bp encoding 580 amino acids. Conserved motifs in the GRAS domain are detected, including VHIID, PFYRE, SAW and two LHR motifs. Within the VHII motif, the P-H-N-D-Q-L residues are entirely maintained. Phylogenetic analysis reveals that Ha- GRASL belongs to the SCARECROW LIKE4/7 ( SCL4/7) subfamily of the GRAS consensus tree. Accumulation of Ha- GRASL mRNA at the adaxial boundaries from P6/P7 leaf primordia suggests a role of Ha- GRASL in the initiation of median and basal axillary meristems ( AMs) of sunflower. When Ha- GRASL is over-expressed in Arabidopsis wild-type plants, the number of lateral bolts increases differently from untransformed plants. However, Ha- GRASL slightly affects the lateral suppressor ( las-4-) mutation. Therefore, we hypothesise that Ha- GRASL and LAS are not functionally equivalent. The over-expression of Ha- GRASL reduces metabolic flow of gibberellins ( GAs) in Arabidopsis and this modification could be relevant in AM development. Phylogenetic analysis includes LAS and SCL4/7 in the same major clade, suggesting a more recent separation of these genes with respect to other GRAS members. We propose that some features of their ancestor, as well as AM initiation and outgrowth, are partially retained in both LAS and SCL4/7. [ABSTRACT FROM AUTHOR]

Rice ( Oryza sativa L.) can successfully germinate and grow even when flooded. Rice varieties possessing the submergence 1A ( Sub1A) gene display a distinct flooding-tolerant phenotype, associated with lower carbohydrate consumption and restriction of the fast-elongation phenotype typical of flooding-intolerant rice varieties. Calcineurin B-like interacting protein kinase 15 (CIPK15) was recently indicated as a key regulator of α-amylases under oxygen deprivation, linked to both rice germination and flooding tolerance in adult plants. It is still unknown whether the Sub1A- and CIPK15-mediated pathways act as complementary processes for rice survival under O deprivation. In adult plants Sub1A and CIPK15 may perhaps play an antagonistic role in terms of carbohydrate consumption, with Sub1A acting as a starch degradation repressor and CIPK15 as an activator. In this study, we analysed sugar metabolism in the stem of rice plants under water submergence by selecting cultivars with different traits associated with flooding survival. The relation between the Sub1A and the CIPK15 pathways was investigated. The results show that under O deprivation, the CIPK15 pathway is repressed in the tolerant, Sub1A-containing, FR13A variety. CIPK15 is likely to play a role in the up-regulation of Ramy3D in flooding-intolerant rice varieties that display fast elongation under flooding and that do not possess Sub1A. [ABSTRACT FROM AUTHOR]