General goals and objectives
Provides scientific basis to control the fungus (Alternaria sp.) causing stem end rot disease on pitaya by applying endophytic bacteria.
Specific goals and objectives
- Isolating, identifying and classifying at least 05 endophytic bacteria from pitaya and some native grass species with potential against stem end rot on pitaya in Binh Thuan province.
- Evaluating the antagonistic effect against Alternaria sp., the causal agent of stem end rot disease on pitaya, by isolated endophytic bacteria under laboratory conditions.
- Evaluating the ability in promoting the growth of pitaya seedlings of endophytic bacteria isolated in nursery conditions in Binh Thuan province.

Theoretical results:
+ Isolated and identified the causal agent of stem end rot on pitaya is the fungus Alternaria alternata strain YZU
+ Isolated 150 endophytic bacteria from plant samples and 36 strains of them were able to inhibit the growth of mycelium causing stem end rot disease. A mong 36 isolates, 15 strains generated the diameter of the antifungal zone from 11-20 mm, which were selected for the next experiments. From the results of experiments with bacterial culture, 6/36 strains have the ability to produce antifungal agent A. alternata, accounting for 16.67%.
The sequencing results of 16S rDNA gene fragments of 15 bacterial strains showed that they belonged to 3 main groups: Curtobacterium flaccumfaciens, Bacillus, and Pseudomonas. The DNA sequences obtained from these strains were deposited on the Genbank portal with the accession number from ON352656 to ON352670.
The results also showed that 15 strains also produced some plant growth-promoting traits such as the production of IAA, phosphate solubilization, nitrogen fixation, and the production of external enzymes.
+ Temperature and combination of isolates (ratio 1:1) had a clear influence on the antagonistic activity of isolates
+ Selected endophytic bacteria stimulated plant growth at different levels in in vitro and in vivo conditions.
+ Selected endophytic bacteria also stimulated plant growth at different levels in nursery conditions

- Isolated and identified endophytic bacteria from native grasses that showed strong antagonistic activity against the fungus caused stem rot on pitaya.
- The selected isolates presented a stimulation of plant growth in laboratory and nursery conditions.

- Scientific papers in referred journals (list):
+ Do Quang Trung, Nguyen Thi Thu Hang, Dinh Mai Van, Pham Bich Ngoc, Luu The Anh 2022, “Screening of Endophytic Bacteria isolated from weed plant to Biocontrol Stem rot Disease on Pitaya (Hylocereus undatus)”, Brazilian Archives of Biology and Technology,  65: e22200749. https://doi.org/10.1590/1678-4324-2022200749.
+ Do Quang Trung, Luu The Anh, Dinh Mai Van, Pham Bich Ngoc, Nguyen Thi Thu Hang 2022, “Biocontrol of Alternaria alternata YZU, a causal of stem end rot disease on pitaya, with soil phosphate solubilizing bacteria”. Hue University Journal of Science: Natural Science (Accepted).