I9K aims to respond to the challenges of the Kiwi industry by creating a group of excellence that will adopt innovative strategies and agricultural practices that generate greater productivity, enhancing the sector's competitiveness in new markets.
In this context, the main results to be achieved in the scope of i9K are:
• Mapping of the main producing regions based on abiotic and biotic factors. Implementation of programs that identify the most vulnerable regions based on the prediction of the direct and indirect effects of abiotic and biotic factors;
• Methods of mitigation and control of Psa through the use of antagonists with possibility of being used in real context;
• Methods of mitigation and control of Psa in pollen with the possibility of being used in real context;
• Methods that boost the immune system of the plant with the possibility of being used in real context;
• Identification of natural reservoirs of Psa whose management will be included in the Technical Manual;
• Identification of varieties adapted to the climatic of the two main producing regions, Entre Douro e Minho and Beira Litoral, with high productive capacity and resistance / tolerance to Psa;
• Innovative pollen application methods adapted to the national context (size of plots, soil and climatic conditions, pergola vs cross-section, etc.).
I9Kiwi aims to improve the country's competitiveness, focusing exclusively on primary production activities of the kiwi line through various types of innovation, including product and process innovation. I9Kiwi gathers the necessary skills to fill evident gaps in the phytosanitary sector and in the quality and diversity of cultivars and pollen associated with high production costs.
Summary of activities to date:
• Biological Diversity of Psa Populations.
Aims to characterize the Psa populations present in Portuguese C98 orchards that have distinct abiotic conditions (North and Center of Portugal), representative of the climatic diversity to which the crop is subjected. In total, 1673 strains putatively identified as Psa were isolated and later confirmed. The biovar was determined and all isolates were typed using BOX-PCR and VTNR methodology. The results showed that Psa populations in Portuguese orchards are heterogeneous. Such heterogeneity was found in each of the orchards and between orchards. Moreover, the structure of Psa populations varied over time in the same plant.
• Assessing Genetic Diversity among Different Psa Populations.
Determined the genomes of six Psa strains isolated from symptomatic leaves of Actinidia chinensis var. deliciosa. Mean nucleotide identity values were greater than 99% similarity with Psa biovar 3 reference strains. Genomic differences found between these strains confirm the genetic diversity described for the Psa population in Portugal.
• Comparative genomics allowed finding differences between strains of pseudomonas Syringae PV. Actinidiae isolated in Portugal.
In this study, the draft genome of six Psa isolates obtained from symptomatic leaves of Actinidia chinensis cv. deliciosa in Portuguese orchards was determined to estimate the genes that constitute the shared genome, the accessory genome and the pangenome. To our knowledge, there is only a draft genome of one Portuguese strain, CRA-FRU 14.08 isolated in 2010 in the first Psa outbreak in Portugal.
The genome of this and other representative strains from the five Psa populations were used for comparative genomics analyses. These analyses revealed important differences among Psa strains and between these strains and the first Portuguese CRA-FRU isolate. Genomic island prediction tools predicted the occurrence of a pathogenicity island in two strains and resistance islands in four. The coexistence in the same plant of strains with different virulence repertoire previously described by other authors was also confirmed. These results reflect a clear intraspecific diversity in the Portuguese isolates and a mechanism of evolution and adaptation of the underlying genome.
• The leaf bacterial microbiota of female and male kiwifruit plants in distinct seasons: evaluation of the impact of pseudomonas Syringae PV. Actinidiae.
Abiotic factors and plant genus are known to influence disease outcome. Fifty bacterial operational taxonomic units were identified and assigned to five Phyla distributed over 14 different families and 23 genera. Leaves of healthy female and male kiwifruit plants share most of the identified bacterial populations, which undergo major seasonal changes.
The presence of Psa induced profound changes in leaf bacterial community structures, translated into a reduction in the relative abundance of previously dominant genera that had been found on healthy plants; namely, Hymenobacter, Sphingomonas, and Massilia spp. The impact of Psa was less pronounced on the bacterial community structure of male plants in both seasons.
• The culturable microbiome of the phyllosphere as a source of innovative solutions to combat plant diseases.
A total of 455 isolates, grouped by 135 RAPD clusters, were distributed taxonomically by five classes and 58 species. Some of the isolates corresponded to populations identified by crop-independent methodology. Others were only identified by the cultivation effort. In both approaches genera already described as having the potential to act as antagonists or as promoters of plant defense mechanisms were detected.
Two genera and three species new to science were identified that will be formally described and their biopesticidal potential will be evaluated.
• The microbiota of the kiwi phyllosphere as a reservoir for PGPB and biological control for Psa.
This study aimed to identify potential antagonists against Psa and Plant Growth Promoting Bacteria (PGPB) from the microbiota naturally present in the kiwifruit phyllosphere. One hundred and twenty bacterial isolates belonging to 23 genera previously described by the team were tested for various parameters, namely: phosphate solubilization, siderophore production, ammonia production and auxins, with emphasis on 3-Indole Acetic Acid (IAA). Of the strains tested, 20 were positive for all parameters suggesting that these bacteria have the potential to integrate into biobased solutions for more sustainable management practices. Among all the isolates tested, Bacillus pumilus bacteria was able to inhibit Psa growth with the formation of an inhibitory halo around the colony with an area of 228.17 mm2.
• Identification, characterization and antagonistic activity of basteria isolated from a Psa-free kiwi orchard.
The main objectives of this work were to identify microbial biopesticides for control of the above phytopathogenic bacteria and/or plant growth promoting bacteria (BPCP) isolated from populations naturally present in the phyllosphere of domestic kiwi orchards. A culture collection of endophytic and epiphytic bacteria isolated from five orchards located in the main kiwi producing areas (Viana do Castelo, Guimarães, Albergaria-a-Nova and Montemor-o-Velho) was compiled, accounting for a total of 2331 strains. Of these, 975 were negative in molecular analysis for Psa.
• Development of the I9Kiwi platform.
A monitoring system, composed of hardware and software components, which will be integrated in a "symbiotic" way to collect as much information as possible about the conditioning parameters of both production and crop diseases, thus making it possible to correlate abiotic factors with diseases and production rates. The application will also have the ability to generate alerts for better management by producers.