Heat stress is a major limiting factor of grapevine production and quality. Acclimation and recovery are essential to ensure plant survival, and the recovery mechanisms can be independent of the heat response mechanisms. An experimental set up with and without acclimation to heat followed by recovery [stepwise acclimation and recovery (SAR) and stepwise recovery (SR), respectively] was applied to two grapevine varieties, Touriga Nacional (TN), and Trincadeira (TR), with different tolerance to abiotic stress. Major differences were found between leaves of SAR and SR, especially after recovery; in SAR, almost all parameters returned to basal levels while in SR they remained altered. Acclimation led to a swifter and short-term antioxidative response, affecting the plant to a lesser extent than SR. Significant differences were found among varieties: upon stress, TN significantly increased ascorbate and glutathione reduction levels, boosting the cell's redox-buffering capacity, while TR needed to synthesize both metabolites, its response being insufficient to keep the redox state at working levels. TR was affected by stress for a longer period and the up-regulation pattern of antioxidative stress genes was more obvious. In TN, heat shock proteins were significantly induced, but the canonical heat-stress gene signature was not evident probably because no shutdown of the housekeeping metabolism was needed.

The objective of this work was to evaluate the effect of foliar spraying with bacterial biocontrol agents (BBAs) on the control of common bacterial blight (CBB) of bean, and on the induction of systemic resistance in bean plants. CBB control by BBAs was evaluated by spraying bean leaves 48 and 24 hours before and after pathogen inoculation (BPI and API, respectively), with: DFs93, Bacillus cereus; DFs513, Pseudomonas veronii; DFs769, B. cereus; the C01 combination, DFs93 + DFs769 + DFs831 (Pseudomonas fluorescens); the C03 combination, DFs348 (Bacillus sp.) + DFs769 + DFs831; and water (control). Systemic effects were analyzed after spraying DFs513, DFs769, C03, and water 72 and 48 hours BPI. Phaseolin production induced by DFs348, DFs513, DFs769, DFs831, and water was also assessed. DFs513, DFs769, and C03 significantly reduced disease incidence (area under disease progress curve), regardless of spraying time and disease severity when sprayed 72 and 48 hours BPI. The DFs769 and DFs831 isolates induced the accumulation of phytoalexin (phaseolin). Therefore, DFs513, DFs769, and C03 show potential for the biocontrol of CBB when applied preventively on bean leaves, besides inducing systemic resistance.

The bacterial biocontrol agents (BCAs) treatments were used for seed microbiolization; the bacterial biocontrol agents (BCAs) used selected from previous study on the control of Xanthomonasaxonopodis pv. phaseoli Xap) includes: Bacillus (DFs093, DFs348 and DFs769), Pseudomonas (DFs513, DFs831 and DFs842), Rhodococcus (DFs843 and DFs912), and the combinations C01 (DFs093+DFs769+DFs831), C02 (DFs093+DFs769+DFs842) and C03 (DFs093+DFs769+DFs348). Sixteen (16) Xap strains were collected from several Brazilian regions, and were inoculated in cotyledonary leaves. The symptom development was followed for 10 days. The treatments were compared by the area under the disease progress curve for disease incidence, severity, and index. In general, majority of the BCAs reduced, to some degree, the disease caused by different Xap strains. The combination C01, and the isolate DFs831 resulted in highest mean disease control. The data from this study suggest a relationship between the region of origin of Xap strain and the efficacy of BCA to control the disease caused by it. The use of combinations of these organisms increased the efficacy of the biocontrol of several strains of the same pathogen. A strain-BCA interaction was shown by data collected from this study, which evidence the importance of selecting a BCA or a combination of BCAs with a wider spectrum of action.