Avocado (Persea americana) and cherimoya (Annona cherimola) crop ontologies facilitate data interoperability among different descriptors in biological databases

Subtropical fruits, like avocado and cherimoya, are key crops for food security in a wide range of countries, with an increasing commercial importance worldwide. Even though their importance is starting to be recognized and high throughput sequencing approaches are currently being used to characterize genome­wide patterns from natural diversity populations and breeding stocks, currently ontological available information for these subtropical fruits crops is scarce and often not based in internationally standardized formats. Thus, the challenge to correlate the expanding molecular information data available with plant phenotype and crop traits remains an important issue in breeding programs for these crops. With the aim to facilitate future analyses we present a controlled vocabulary for harmonizing the annotation of phenotypic and genomic data for these crops. These new ontologies represent an extended ontology to fit avocado and cherimoya traits commonly used in variety descriptions, mainly established by Biodiversity International and the International Union for the Protection of New Varieties of Plants (UPOV), but also custom ad hoc descriptors. The developed ontology includes measurable or observable characteristics of plants as well as abiotic and biotic stress susceptibility. The resource is available in standard OBO formats ready to be used in GMOD and Tripal inspired biological databases to allow data sharing and reusability. The approach followed here can be of interest to other crops in which standardized ontologies are still missing.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work is supported by MINECO (AGL2013-43732- R and AGL2016-77267-R) to Iñaki Hormaza, (RYC-2011-08839) to Antonio Matas and (BES-2014-068832) to Alicia Talavera Júdez

The diversity of the pollen tube pathway in plants: toward an increasing control by the sporophyte

12 Pags.- 1 Fig.Plants, unlike animals, alternate multicellular diploid, and haploid generations in their life cycle. While this is widespread all along the plant kingdom, the size and autonomy of the diploid sporophyte and the haploid gametophyte generations vary along evolution. Vascular plants show an evolutionary trend toward a reduction of the gametophyte, reflected both in size and lifespan, together with an increasing dependence from the sporophyte. This has resulted in an overlooking of the importance of the gametophytic phase in the evolution of higher plants. This reliance on the sporophyte is most notorious along the pollen tube journey, where the male gametophytes have to travel a long way inside the sporophyte to reach the female gametophyte. Along evolution, there is a change in the scenery of the pollen tube pathway that favors pollen competition and selection. This trend, toward apparently making complicated what could be simple, appears to be related to an increasing control of the sporophyte over the gametophyte with implications for understanding plant evolution.This work was supported by Ministerio de Economía y Competitividad – European Regional Development Fund, European Union (AGL2012-40239, AGL2013-43732-R, and Recupera2020) and Gob. Aragón A-43. JL was supported by a Juan de la Cierva postdoctoral grant of the Spanish Ministry of Science and Innovation.Peer reviewe

Effect of temperature on pollen tube kinetics and dynamics in sweet cherry, Prunus avium (Rosaceae)

The article is available at: http://www.amjbot.org/cgi/content/full/91/4/558Prevailing ambient temperature during the reproductive phase is one of several important factors for seed and fruit set in different plant species, and its consequences on reproductive success may increase with global warming. The effect of temperature on pollen performance was evaluated in sweet cherry (Prunus avium L.), comparing as pollen donors two cultivars that differ in their adaptation to temperature. ‘Sunburst’ is a cultivar that originated in Canada with a pedigree of cultivars from Northern Europe, while ‘Cristobalina’ is a cultivar native to southeast Spain, adapted to warmer conditions. Temperature effects were tested either in controlled-temperature chambers or in the field in a plastic cage. In both genotypes, an increase in temperature reduced pollen germination, but accelerated pollen tube growth. However, a different genotypic response, which reflected the overall adaptation of the pollen donor, was obtained for pollen tube dynamics, expressed as the census of the microgametophyte population that successfully reached the base of the style. While both cultivars performed similarly at 20°C, the microgametophyte population was reduced at 30°C for Sunburst and at 10°C for Cristobalina. These results indicate a differential genotypic response to temperature during the reproductive phase, which could be important in terms of the time needed for a plant species to adapt to rapid temperature changes.A. H. was supported by an AECI and an SIA-DGA fellowship, and financial support for this work was provided by INIA (project grant RTA 01-103).Peer reviewe

The effect of temperature on pollen germination, pollen tube growth, and stigmatic receptivity in peach

The definitive version is available at: http://www.thieme.de/fz/plantbiology/Temperature is a major climatic factor that limits geographical distribution of plant species, and the reproductive phase has proven to be one of the most temperature-vulnerable stages. Here, we have used peach to evaluate the effect of temperature on some processes of the progamic phase, from pollination to the arrival of pollen tubes in the ovary. Within the range of temperatures studied, 20 °C in the laboratory and, on average, 5.7 °C in the field, the results show an accelerating effect of increasing temperature on pollen germination and pollen tube growth kinetics, as well as an increase in the number of pollen tubes that reach the style base. For the last two parameters, although the range of temperature registered in the field was much lower, the results obtained in the laboratory paralleled those obtained in the field. Increasing temperatures drastically reduced stigmatic receptivity. Reduction was sequential, with stigmas first losing the capacity to sustain pollen tube penetration to the transmitting tissue, then their capacity to offer support for pollen germination and, finally, their capacity to support pollen grain adhesion. Within a species-specific range of temperature, this apparent opposite effect of temperature on the male and female side could provide plants with the plasticity to withstand changing environmental effects, ensuring a good level of fertilization.A. H. was supported by an AECI, SIA-DGA, and a CSIC fellowship. Financial support for this work was provided by project grants INIA-RTA 01-103, CICYT AGL2003-05318-C02-01 and by the “Grupo de Investigación Consolidado de Aragón: A-02, A-43”.Peer reviewe

Fruiting pattern in longan, Dimocarpus longan: from pollination to aril development

18 Pags.- 1 Tabl.- 6 Figs. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1744-7348In most fleshy fruits, the edible part of the fruit is formed either by the pericarp derived from the ovary wall or by an engrossed receptacle. However, in a number of fruit tree species the edible part is the aril, an outgrowth of the ovule that envelops the seed, and there is a paucity of information on fruit development and fruiting pattern in these crops. To fill this gap, in this work, we have characterised the progamic phase, fruit development and fruit/fruitlet drop in longan, Dimocarpus longan. The progamic phase from pollination to fertilisation took just 3 days; the pollen tubes arrived to the base of the style in 1 day, reached the locule 1 day later and penetrated the ovules 3 days after pollination. Only one of the two ovules present in each longan flower fertilised. However, this did not result in rapid fruitlet growth, since a very slow fruit development occurred up to 6 weeks after flowering. Pollination was required for fruiting and unpollinated flowers dropped 9 days after anthesis. Only 7% of the female flowers produced became fruits. There was a first flower/fruitlet drop 2–4 weeks after flowering that appeared to be related to lack of fertilisation followed by a second fruitlet drop 5–6 weeks after flowering, concomitantly with the rapid growth of the embryo and the aril, that appears to be related to competition for nutrients. These results set a frameline to understand fruiting in tree species in which the edible part of the fruit is a fleshy aril.This work was supported by the Spanish Ministerio de Economía y Competitividad–European Regional Development Fund, European Union (AGL2013-43732-R and AGL2012-40239, and Recupera2020) and Gobierno de Aragón A-43. V. T. P. was supported by a PhD scholarship from the Consejo Superior de Investigaciones Científicas (CSIC), Spain, and Vietnam Academy of Science and Technology (VAST).Peer reviewe

Low temperature storage and in vitro germination of cherimoya (Annona cherimola Mill.) pollen

Due to the protogynous dichogamy of cherimoya and to the absence of proper pollinating vectors, hand-pollination with fresh pollen is a common practice for cherimoya commercial production. In order to optimize the process of hand-pollination, in this work we have studied the conservation of cherimoya pollen at –20, -80 and –196ºC for up to three months. In vitro pollen germination of fresh pollen was 57.1% and it was progressively reduced with conservation time at the three temperatures studied reaching a minimum after three months of storage of 10.4 %, 14.2% and 13.6% at –20, -80 and –196ºC, respectively. Differences in germination among temperatures were only significant during the first two weeks of storage. Field pollinations with pollen stored for up to three months at the three temperatures show no yield differences compared to pollinations performed with fresh pollen. The results indicate that pollen collected and stored at sub-zero temperatures at the beginning of the cherimoya blooming season can be used along the whole blooming season avoiding the need of collecting fresh pollen daily.Financial support for this work was provided by MCYT (Project Grant AGL2003-05318-C02-01).Peer reviewe

Self-Incompatibility in Apricot: Identifying Pollination Requirements to Optimize Fruit Production

In recent years, an important renewal of apricot cultivars is taking place worldwide, with the introduction of many new releases. Self-incompatible genotypes tolerant to the sharka disease caused by the plum pox virus (PPV), which can severely reduce fruit production and quality, are being used as parents in most breeding programs. As a result, the self-incompatibility trait present in most of those accessions can be transmitted to the offspring, leading to the release of new self-incompatible cultivars. This situation can considerably affect apricot management, since pollination requirements were traditionally not considered in this crop and information is lacking for many cultivars. Thus, the objective of this work was to determine the pollination requirements of a group of new apricot cultivars by molecular identification of the S-alleles through PCR amplification of RNase and SFB regions with different primer combinations. The S-genotype of 66 apricot cultivars is reported, 41 for the first time. Forty-nine cultivars were considered self-compatible and 12 self-incompatible, which were allocated in their corresponding incompatibility groups. Additionally, the available information was reviewed and added to the new results obtained, resulting in a compilation of the pollination requirements of 235 apricot cultivars. This information will allow an efficient selection of parents in apricot breeding programs, the proper design of new orchards, and the identification and solution of production problems associated with a lack of fruit set in established orchards. The diversity at the S-locus observed in the cultivars developed in breeding programs indicates a possible genetic bottleneck due to the use of a reduced number of parents.Publishe

Técnicas experimentales para el control de la optimización del riego y recursos hídricos en el contexto del sur de España.

La escasez de recursos hídricos es uno de los principales problemas a los que se enfrenta la sociedad actual. Este hecho adquiere una mayor relevancia en áreas mediterráneas y en un contexto de cambio climático, donde confluyen actividades muy demandantes como el turismo y, cada vez en mayor medida, la agricultura de regadío. Por ello, existe una necesidad de poner en marcha una serie de mecanismos de adaptación que ayuden a reducir y optimizar dicho gasto, como pueden ser la regeneración de aguas, la desalación una digitalización del agro, un control edáfico del riego, los umbrales hidrológicos del suelo o la monitorización mediante sondas de humedad. En este sentido, el objetivo de este estudio consiste en diseñar un sistema de monitoreo para evaluar las repercusiones agrícolas de la aplicación de diferentes tipos de riego en cultivos subtropicales, implementado en una parcela experimental del Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” (Málaga). Detalladamente, analiza la dinámica pluviométrica en un ambiente mediterráneo de condiciones climáticas secas-semiáridas y su incidencia en la dinámica hidrológica del suelo.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Male Meiosis as a Biomarker for Endo- to Ecodormancy Transition in Apricot

Dormancy is an adaptive strategy in plants to survive under unfavorable climatic conditions during winter. In temperate regions, most fruit trees need exposure to a certain period of low temperatures to overcome endodormancy. After endodormancy release, exposure to warm temperatures is needed to flower (ecodormancy). Chilling and heat requirements are genetically determined and, therefore, are specific for each species and cultivar. The lack of sufficient winter chilling can cause failures in flowering and fruiting, thereby compromising yield. Thus, the knowledge of the chilling and heat requirements is essential to optimize cultivar selection for different edaphoclimatic conditions. However, the lack of phenological or biological markers linked to the dormant and forcing periods makes it difficult to establish the end of endodormancy. This has led to indirect estimates that are usually not valid in different agroclimatic conditions. The increasing number of milder winters caused by climatic change and the continuous release of new cultivars emphasize the necessity of a proper biological marker linked to the endo- to ecodormancy transition for an accurate estimation of the agroclimatic requirements (AR) of each cultivar. In this work, male meiosis is evaluated as a biomarker to determine endodormancy release and to estimate both chilling and heat requirements in apricot. For this purpose, pollen development was characterized histochemically in 20 cultivars over 8 years, and the developmental stages were related to dormancy. Results were compared to three approaches that indirectly estimate the breaking of dormancy: an experimental methodology by evaluating bud growth in shoots collected periodically throughout the winter months and transferred to forcing chambers over 3 years, and two statistical approaches that relate seasonal temperatures and blooming dates in a series of 11–20 years by correlation and partial least square regression. The results disclose that male meiosis is a possible biomarker to determine the end of endodormancy and estimate AR in apricot.Publishe