Banca de DEFESA: KAROL ALVES BARROSO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : KAROL ALVES BARROSO
DATA : 30/08/2023
HORA: 09:00
LOCAL: Google Meet
TÍTULO:

Managing melon root rot diseases via soil incorporation of plant residue and bioactive inducers and controlling plant viruses via RNA interference

PALAVRAS-CHAVES:

Cucumis melo, soil-borne pathogens, potato virus Y, RNA interference

PÁGINAS: 72
RESUMO:

CHAPTER 1: Root rot is reduced and soil microbial communities increase by incorporation of jack bean and the use of bioactive inducers in melon growing areas

ABSTRACT: Brazil is one of the largest melon (Cucumis melo) producers in the world, but the production is being jeopardized by soil-borne pathogens and the soil microbial community is out of balance. Current management are inefficient in controlling root rot pathogens; therefore, innovative ways to manage this disease complex is much needed. This work aimed to evaluate the effect of integrated of combining strategies in managing root rot in melon plants and the effects on the soil’s biological attributes as compared to traditional management in a melon-producing area. Experiments were first performed in a greenhouse and the treatments consisted of incorporating plant material, crambe (Crambe abyssinica) and Jack bean (Canavalia ensiformis) and using the bioactive inducers Compost Aid® and Copper Crop®, compared to treatments used by melon-growers as a control. The treatments that showed the best results in the greenhouse were chosen to be used in the field. Field experiments were performed in two different melon-producing areas with histories of root rot disease in melon plants. Overall, the treatments containing jack bean materials were superior to the control treatment. The treatment, jack bean incorporation combined with the use of Compost Aid® reduced the incidence of the disease by 61.29% (Exp. 1) and 40.62% (Exp. 2), and reduced the severity of the disease by 59.48% (Exp. 1) and 54.21% (Exp. 2), compared to the control. It also increased productivity by 103.46% (Exp. 1) and 84.28% (Exp. 2) compared to the control. The same treatment provided the highest averages for basal soil respiration, microbial biomass carbon, and numbers of total bacteria, sporulating bacteria, total actinomycetes, and total fungi colonies forming units compared to the control treatment. In these treatments, microbial biomass was more efficient in using organic compounds, making them more readily available to melon plants. This was the most suitable treatment to suppress root rot disease in melon in our trials, and it is being integrated by local growers as an efficient strategy to manage root rot diseases and ensure microbiological balance under traditional melon management in the Brazilian Semiarid region.

CHAPTER 2: The genomic region matters when synthesizing dsRNA for plant virus suppression via RNAi

ABSTRACT: Potato virus Y is one of the most economically important plant viruses in the world. Since no efficient control methods are available, RNA interference (RNAi)-based crop protection strategy has become a promising option for the control of plant pathogens. In this context, the aim of this study was to test the hypothesis that dsRNA molecules derived from different genomic regions would induce different viral suppression by RNAi, and evaluate the fate and movement of the dsRNA molecules inside tobacco plants. Regions with a high concentration of 21nt siRNAs, detected by a small RNA profiles analysis, were selected to synthesize dsRNA (~600 bp) from each cistron in suppressing PVY infection. The dsRNAs synthesized from CP, HC-PRO, and NIb cistrons were applied and two weeks after viral inoculation, PVY symptoms were assessed. The translocation of the applied dsRNA molecules was also evaluated for 14 days, and in this step, no virus inoculation was performed. RT-qPCR was performed on the total RNA extracted from the localized and systemic leaves, and to investigate whether dsRNAs move as dsRNAs or siRNAs within the plant, we used the stem-loop RT-PCR methodology. The movement of dsRNA molecules within the plant was also investigated by labeling the dsRNA with the fluorescent dye cyanine 3-UTP (Cy3-UTP). The dsRNAs applied protected treated plants against PVY infection, and HC-PRO-dsRNA induced greater protection, entered, and moved fast compared to CP and NIb-dsRNAs, this fact was confirmed by the fluorescence signal of Dsrna-cy3 in treated leaves. DsRNAs and siRNAs were detected in systemic leaves after 24 hours of dsRNA application, demonstrating that these molecules translocated systemically inside the plant, and remained for at least 14 days. The synthesis and application of exogenous dsRNAs targeting the HC-PRO genomic region of PVY proved to be a promising technique for controlling this disease.

MEMBROS DA BANCA:
Interna - ***.979.544-** - ANDREIA MITSA PAIVA NEGREIROS - UFERSA
Externa à Instituição - EDICLEIDE MACEDO DA SILVA - UNESP
Interna - 2578315 - JAILMA SUERDA SILVA DE LIMA
Presidente - 1544411 - MARCIA MICHELLE DE QUEIROZ AMBROSIO
Interno - 1445570 - RUI SALES JUNIOR
Interno - ***.076.546-** - WASHINGTON LUÍS DA SILVA - CAES