An improved and cost-effective cDNA-AFLP method to investigate transcription-derived products when high throughput sequencing is not available

TraeALDH7B1-5A, encoding aldehyde dehydrogenase 7 in wheat, confers improved drought tolerance in Arabidopsis

TraeALDH7B1 - 5A , encoding aldehyde dehydrogenase 7 in wheat, conferred significant drought tolerance to Arabidopsis , supported by molecular biological and physiological experiments. Drought stress significantly affects wheat yields. Aldehyde dehydrogenase (ALDH) is a family of enzymes catalyzing the irreversible conversion of aldehydes into acids to decrease the damage caused by abiotic stresses. However, no wheat ALDH member has been functionally characterized to date. Here, we obtained a differentially expressed EST encoding ALDH7 from a cDNA-AFLP library of wheat that was treated with polyethylene glycol 6000. The three full-length homologs of TraeALDH7B1 were isolated by searching the NCBI database and by homolog-based cloning method. Using nulli-tetrasomic lines we located them on wheat chromosomes 5A, 5B and 5D, and named them as TraeALDH7B1-5A, -5B and -5D, respectively. Gene expression profiles indicated that the expressions of all three genes were induced in roots, leaves, culms and spikelets under drought and salt stresses. Enzymatic activity analysis showed that TraeALDH7B1-5A had acetaldehyde dehydrogenase activity. For further functional analysis, we developed transgenic Arabidopsis lines overexpressing TraeALDH7B1-5A driven by the cauliflower mosaic virus 35S promoter. Compared with wild type Arabidopsis, 35S::TraeALDH7B1-5A plants significantly enhanced the tolerance to drought stress, which was demonstrated by up-regulation of stress responsive genes and physiological evidence of primary root length, maintenance of water retention and contents of chlorophyll and MDA. The combined results indicated that TraeALDH7B1-5A is an important drought responsive gene for genetic transformation to improve drought tolerance in crops.

Robust ordered mRNA differential display: an improved method for global gene expression profiling

Global gene expression profiling (GGEP) plays a pivotal role in biological research. We developed an improved GGEP method called "robust ordered mRNA differential display (RoDD)" by combining mRNA differential display (DD) and complementary DNA amplified fragment length polymorphisms (cDNA-AFLP) using elaborately designed primers and a poly (dT:A) replacement technique. Redundancy was minimized by bead-based isolation and coverage was improved by using restriction enzymes that recognized 4-bp sites. This method offers the common virtues of gel-based methods along with the reliability of cDNA-AFLP. The most significant advantage of RoDD over current gel-based methods is greatly improved coverage and minimized redundancy.