Elevated activities of cytosolic fructose-1,6-bisphosphatase (cyFBPase) and sedoheptulose-1,7-bisphosphatase (SBPase) are associated with higher yields in plants.  In this study, the expression levels of the cyFBPase and SBPase genes were increased by overexpressing rape (Brassica napus) cDNA in tobacco (Nicotiana tabacum) plants.  The transgenic plants co-expressing cyFBPase and SBPase (TpFS), or expressing single cyFBPase (TpF) or SBPase (TpS) had 1.77-, 1.55-, 1.23-fold cyFBPase and 1.45-, 1.12-, 1.36-fold SBPase activities as compared to the wild-type (WT), respectively.  Photosynthesis rates of TpF, TpS and TpFS increased 4, 20 and 25% compared with WT plants.  The SBPase and cyFBPase positively regulated each other and functioned synergistically in transgenic tobacco plants.  In addition, the sucrose contents of the three transgenic plants were higher than that of WT plants.  The starch accumulation of the TpFS and TpS plants was improved by 53 and 37%, but slightly decreased in TpF plants.  Moreover, the transgenic tobacco plants harbouring SBPase and/or cyFBPase genes showed improvements in their growth, biomass, dry weight, plant height, stem diameter, leaf size, flower number, and pod weight.  In conclusion, co-expression of SBPase and cyFBPase may pave a new way for improving crop yield in agricultural applications.

The development of genetically modified crops requires new promoters and regulatory regions to achieve high gene expression and/or tissue-specific expression patterns in plants. To obtain promoter sequences of plants with new properties, we analyzed the expression traits of the cotton (Gossypium hirsutum) translation elongation factor 1A gene family. The results showed that the GhEF1A8 gene is highly expressed in different organs of cotton plants, and showed much higher transcript levels in stems and leaves. Its promoter (GhEF1A1.7) and the 5´ untranslated region (5´ UTR), comprising a regulatory region named PGhEF1A8, were isolated from cotton and studied in stably transformed tobacco plants. The regulatory region sequences were fused to the β-glucuronidase (GUS) reporter gene to characterize its expression pattern in tobacco. Histochemical and fluorometric GUS activity assays demonstrated that PGhEF1A8 could direct GUS gene expression in all tissues and organs in transgenic tobacco, including leaves, stems, flowers, and roots. The level of GUS activity in the leaves and stems was significantly higher than in cauliflower mosaic virus (CaMV) 35S promoter::GUS plants, but as same as CaMV 35S promoter::GUS plants in flower and root tissues. GUS expression levels decreased 2–10-fold when the 5´ UTR was absent from PGhEF1A8. Deletion analysis of the PGhEF1A8 sequence showed that the region −647 to −323 might possess negative elements that repress transgene expression in tobacco plants. The results suggested that the GhEF1A8 regulation region may represent a practical choice to direct high-level constitutive expression of transgenes and could be a valuable new tool in plant genetic engineering.

A novel gene, GhSERK1, was identified in cotton. It encoded a protein belonging to the somatic embryogenesis receptorlike kinase (SERK) family. The genomic sequence of GhSERK1 was 6 920 bp in length, containing a predicted transcriptional start site (TSS). Its full-length cDNA was 2 502 bp, encoding a protein of 627 amino acids. Sequence analysis of GhSERK1 revealed high levels of similarity to other reported SERKs, as well as a conserved intron/exon structure that was unique to members of the SERK family. Expression analysis showed that GhSERK1 mRNA was present in all organs of cotton plants and at different developmental stages, but its transcripts were most abundant in reproductive organs. Compared with that of the male-fertile line, the level of GhSERK1 mRNA was lower in the anther of the male-sterile cotton line, in which the pollen development was defected. Taken together, these findings illustrated that the GhSERK1 play a critical role during the anther formation, and may also have a broad role in other aspects of plant development.