In this study, we aimed to identify common genetic components during stress response responsible for crosstalk among stresses, and to determine the role of differentially expressed genes in Arabidopsis-Botrytis cinerea interaction. Of 1,554 B. cinerea up-regulated genes, 24%, 1.4% and 14% were induced by biotic, abiotic and hormonal treatments, respectively. About 18%, 2.5% and 22% of B. cinerea down-regulated genes were also repressed by the same stress groups. Our transcriptomic analysis indicates that plant responses to all tested stresses can be mediated by commonly regulated genes; and protein-protein interaction network confirms the cross-interaction between proteins regulated by these genes. Upon challenges to individual or multiple stress(es), accumulation of signaling molecules (e.g. hormones) plays a major role in the activation of downstream defense responses. In silico gene analyses enabled us to assess the involvement of RAP2.4 (related to AP2.4) in plant immunity. Arabidopsis RAP2.4 was repressed by B. cinerea, and its mutants enhanced resistance to the same pathogen. To the best of our knowledge, this is the first report demonstrating the role of RAP2.4 in plant defense against B. cinerea. This research can provide a basis for breeding programs to increase tolerance and improve yield performance in crops.

The polymerase chain reaction (PCR) was used to screen embryonic, fetal and adult human cDNA libraries for transcription on chromosome 21q22.1→q22.3. Seventy-three pairs of oligonucleotide primers on chromosome 21, used previously to screen a fetal brain cDNA library, were applied to analyze 41 different cDNA libraries. Only phage eluate (and therefore no DNA isolation) was required for this sensitive screening. Sixty primer pairs were positive with at least one cDNA library, indicating that the majority of primers were derived from transcribed sequences. Even with our most complex human fetal brain cDNA library, we detected only 57% (34/60) of transcribed sequences, illustrating the need to screen multiple human cDNA libraries to determine if transcription occurred. Since only 3/73 clones were present in only one cDNA library, the vast majority of transcribed sequences are present in more than one tissue.

Right and timely expression of the stress regulatory genes is required for plants to compete against abiotic stresses; it necessitates the isolation and characterization of stress-responsive promoters for improving crops' tolerance to abiotic stresses. Dehydration Responsive Element Binding (DREB) regulates the expression of numerous stress-responsive genes in plants and leads an inevitable role in the adaptation of plants to abiotic stresses. In this study, the promoter region of Phoenix dactylifera (Date palm, a major fruit crop of the arid region) PdDREB1G gene was isolated and characterized for the first time. A comparison of the activity of two promoter fragments, 880 bp (DS) and 1.6 kb (DF) of PdDREB1G to AtRD29A was performed. Histochemical assay displayed remarkable GUS staining and RT-qPCR analysis confirmed the induction of GUS expression in T3 plants of transformed tobacco subjected to different abiotic stresses. Furthermore, compared with the widely used AtRD29A promoter, the relative expression of GUS in leaves by DS and DF was three and twofold higher under salt stress, respectively, while it was twofold in polyethylene glycol (PEG) and abscisic acid (ABA) for DS. Under SA stress, DF and DS displayed 1.5 and onefold expression in leaves, respectively. In the root, DS showed a fourfold increased expression in salt, threefold in PEG and ABA, and twofold in SA. Hence, the DS promoter characterized in the present study becomes a choice over RD29A for abiotic stress responses and is useful to develop stress-tolerant transgenic plants by inducing the expression of stress-inducible genes on stress.