RESUMO
Several grapevine (Vitis vinifera L.) cultivars show a tendency to develop parthenocarpic seedless grapes, affecting fruit yield and quality. This reproductive disorder originates in defective ovule fertilization due to a failure in pollen tube growth. Zinc (Zn) is a crucial trace element, playing a vital role in various physiological and metabolic processes. It is particularly essential for the healthy growth of flowers and fruits. Insufficient zinc has been suggested as a potential reason for issues in this development process. This microelement is taken up through a mechanism that involves transporters, including the ZRT-IRT-like protein (ZIP) gene family, associated with the influx of Zn into the cell. In grapevines, 20 genes for ZIP-type transporters have been described. In this study, we analyzed the expression pattern of VviZIP3 during flower development and employ transgenic methods to assess its transcriptional regulation. Furthermore, through computational examination of the promoter region, we identified two CArG boxes, recognized as responsive elements to MADS transcription factors. These factors play a key role in shaping various components of a flower, such as pollen. Our investigation of the VviZIP3 promoter confirms the functionality of these CArG boxes. Overall, our results suggest that the increased expression of VviZIP3 during flowering is likely under the influence of MADS transcription factors.
RESUMO
Parthenocarpy is the development without fertilization of seedless fruits. In the oil palm industry, the development of parthenocarpic fruits is considered an attractive option to increase palm oil production. Previous studies have shown the application of synthetic auxins in Elaeis guineensis, and interspecific O×G hybrids (Elaeis oleifera (Kunth) Cortés × E. guineensis Jacq.) induces parthenocarpy. The aim of this study was to identify the molecular mechanism through transcriptomics and biology system approach to responding to how the application of NAA induces parthenocarpic fruits in oil palm O×G hybrids. The transcriptome changes were studied in three phenological stages (PS) of the inflorescences: i) PS 603, pre-anthesis III, ii) PS 607, anthesis, and iii) PS 700, fertilized female flower. Each PS was treated with NAA, Pollen, and control (any application). The expression profile was studied at three separate times: five minutes (T0), 24 hours (T1), and 48 h post-treatment (T2). The RNA sequencing (RNA seq) approach was used with 27 oil palm O×G hybrids for a total of 81 raw samples. RNA-Seq showed around 445,920 genes. Numerous differentially expressed genes (DEGs) were involved in pollination, flowering, seed development, hormone biosynthesis, and signal transduction. The expression of the most relevant transcription factors (TF) families was variable and dependent on the stage and time post-treatment. In general, NAA treatment expressed differentially more genes than Pollen. Indeed, the gene co-expression network of Pollen was built with fewer nodes than the NAA treatment. The transcriptional profiles of Auxin-responsive protein and Gibberellin-regulated genes involved in parthenocarpy phenomena agreed with those previously reported in other species. The expression of 13 DEGs was validated by RT-qPCR analysis. This detailed knowledge about the molecular mechanisms involved in parthenocarpy could be used to facilitate the future development of genome editing techniques that enable the production of parthenocarpic O×G hybrid cultivars without growth regulator application.
RESUMO
The objective was to study the effectiveness of the growth regulator (ANA + GA3) associated or not to the application of adjuvant and artificial pollination in 'Gefner' atemoya. The experiment was conducted in the experimental orchard at Florida's Tropical Research and Education Center. The experimental design was in a randomized block, with 14 treatments, 10 repetitions and 3 flowers per plot. The highest percentages of fixed fruits were obtained with hand pollination HP and 450 NAA + 1250 GA3 mg L-1 + adjuvant and HP. The use of hand pollination for 'Gefner' atemoya tree proved to be the most efficient method so far. Applying growth regulator without artificial pollination produces parthenocarpic fruits, however with high rate of abortions, and small fruits. Growth regulators together with hand pollination produces small and uneven fruits, and cause reduction in the fruits' titratable acidity. The use of adjuvant caused low fixation and toxicity to fruits, and its use is not recommended.
Assuntos
Reguladores de Crescimento de Plantas , Annona , PolinizaçãoRESUMO
ABSTRACT: The present research aimed to evaluate the effect of applying gibberellic acid (GA3) with hand (HP) or natural pollination (NP) on fruit set and the fruit quality of 'Red' and 'Lessard Thai' sugar apple and 'Gefner' atemoya fruits.This study was performed in an experimental orchard located in Homestead, Florida, USA. The experimental design included randomized blocks, with eight treatments, four replicates and four plants per plot. Treatments included: (1) HP; (2) HP + 10 mg L-1 GA3; (3) HP + 100 mg L-1 GA3; (4) HP + 1,000 mg L-1 GA3; (5) NP; (6) NP + 10 mg L-1 GA3; (7) NP + 100 mg L-1 GA3 and (8) NP + 1,000 mg L-1 GA3. The HP plus 1,000 mg L-1 GA3 promoted fruit setting above 90% over the 14 weeks for all genotypes evaluated. Significant increments for length and total fruit weight were observed. 'Red' sugar apple and atemoya had a reduced number of seeds per fruit. The NP plus GA3 (1,000 mg L-1) was effective in producing high quality seedless 'Gefner' atemoya fruits. This investigationdemonstratedthat GA3 plus hand pollination produced high quality sugar apple and atemoya seeded fruits and in association with natural pollination promoted seedless 'Gefner'atemoya fruits.
RESUMO: O presente trabalho teve como objetivo avaliar o efeito da aplicação de ácido giberélico (GA3) associado com e sem polinização artificial, no pegamento e na qualidade de frutos das pinheiras 'Red' e 'Lessard Thai' e da atemoieira'Gefner'. O experimento foi realizado em pomar localizado em Homestead, EUA. O delineamento experimental foi em blocos casualizados, com oito tratamentos, quatro repetições e quatro plantas por parcela. Os tratamentos utilizados neste experimento foram: 1) Polinização Artificial (PA); 2) PA + 10 mg L-1 GA3; 3) PA + 100 mg L-1 GA3; 4) PA + 1000 mg L-1 GA3; 5) Polinização natural (PN); 6) PN + 10 mg L-1 GA3; 7) PN + 100 mg L-1 GA3; e 8) PN + 1000 mg L-1 GA3. A PA combinada com a concentração de 1000 mg L-1 de GA3 promoveu o estabelecimento de frutos acima de 90% durante as 14 semanas de avaliação para todos os genótipos avaliados. Incrementos significativos para o comprimento e peso dos frutos também foram observados a variedade de pinha "Red" e a atemoia, em que apresentaram redução no número total de sementes.A PN em associação com GA3 (1000 mg L-1) foi eficaz na produção de frutos sem sementes de alta qualidade em atemóia 'Gefner. Estes dados mostram que o GA3, combinado com a polinização manual, produziu frutos com semente de alta qualidade e, em associação com a polinização natural, promoveu frutos sem sementes em atemóia 'Gefner'.
RESUMO
The present research aimed to evaluate the effect of applying gibberellic acid (GA3) with hand (HP) or natural pollination (NP) on fruit set and the fruit quality of Red and Lessard Thai sugar apple and Gefner atemoya fruits.This study was performed in an experimental orchard located in Homestead, Florida, USA. The experimental design included randomized blocks, with eight treatments, four replicates and four plants per plot. Treatments included: (1) HP; (2) HP + 10 mg L-1 GA3; (3) HP + 100 mg L-1 GA3; (4) HP + 1,000 mg L-1 GA3; (5) NP; (6) NP + 10 mg L-1 GA3; (7) NP + 100 mg L-1 GA3 and (8) NP + 1,000 mg L-1 GA3. The HP plus 1,000 mg L-1 GA3 promoted fruit setting above 90% over the 14 weeks for all genotypes evaluated. Significant increments for length and total fruit weight were observed. Red sugar apple and atemoya had a reduced number of seeds per fruit. The NP plus GA3 (1,000 mg L-1) was effective in producing high quality seedless Gefner atemoya fruits. This investigation demonstrated that GA3 plus hand pollination produced high quality sugar apple and atemoya seeded fruits and in association with natural pollination promoted seedless Gefneratemoya fruits.(AU)
O presente trabalho teve como objetivo avaliar o efeito da aplicação de ácido giberélico (GA3) associado com e sem polinização artificial, no pegamento e na qualidade de frutos das pinheiras Red e Lessard Thai e da atemoieiraGefner. O experimento foi realizado em pomar localizado em Homestead, EUA. O delineamento experimental foi em blocos casualizados, com oito tratamentos, quatro repetições e quatro plantas por parcela. Os tratamentos utilizados neste experimento foram: 1) Polinização Artificial (PA); 2) PA + 10 mg L-1 GA3; 3) PA + 100 mg L-1 GA3; 4) PA + 1000 mg L-1 GA3; 5) Polinização natural (PN); 6) PN + 10 mg L-1 GA3; 7) PN + 100 mg L-1 GA3; e 8) PN + 1000 mg L-1 GA3. A PA combinada com a concentração de 1000 mg L-1 de GA3 promoveu o estabelecimento de frutos acima de 90% durante as 14 semanas de avaliação para todos os genótipos avaliados. Incrementos significativos para o comprimento e peso dos frutos também foram observados a variedade de pinha Red e a atemoia, em que apresentaram redução no número total de sementes.A PN em associação com GA3 (1000 mg L-1) foi eficaz na produção de frutos sem sementes de alta qualidade em atemóia Gefner. Estes dados mostram que o GA3, combinado com a polinização manual, produziu frutos com semente de alta qualidade e, em associação com a polinização natural, promoveu frutos sem sementes em atemóia Gefner.(AU)
Assuntos
Annona/efeitos dos fármacos , Annona/crescimento & desenvolvimento , Giberelinas/administração & dosagem , Reguladores de Crescimento de Plantas , Sementes/crescimento & desenvolvimento , Polinização , Estados UnidosRESUMO
The transition from flowering to fruit production, namely fruit set, is crucial to ensure successful sexual plant reproduction. Although studies have described the importance of hormones (i.e. auxin and gibberellins) in controlling fruit set after pollination and fertilization, the role of microRNA-based regulation during ovary development and fruit set is still poorly understood. Here we show that the microRNA159/GAMYB1 and -2 pathway (the miR159/GAMYB1/2 module) is crucial for tomato ovule development and fruit set. MiR159 and SlGAMYBs were expressed in preanthesis ovaries, mainly in meristematic tissues, including developing ovules. SlMIR159-overexpressing tomato cv. Micro-Tom plants exhibited precocious fruit initiation and obligatory parthenocarpy, without modifying fruit shape. Histological analysis showed abnormal ovule development in such plants, which led to the formation of seedless fruits. SlGAMYB1/2 silencing in SlMIR159-overexpressing plants resulted in misregulation of pathways associated with ovule and female gametophyte development and auxin signalling, including AINTEGUMENTA-like genes and the miR167/SlARF8a module. Similarly to SlMIR159-overexpressing plants, SlGAMYB1 was downregulated in ovaries of parthenocarpic mutants with altered responses to gibberellins and auxin. SlGAMYBs likely contribute to fruit initiation by modulating auxin and gibberellin responses, rather than their levels, during ovule and ovary development. Altogether, our results unveil a novel function for the miR159-targeted SlGAMYBs in regulating an agronomically important trait, namely fruit set.