Differences in Flower Transcriptome between Grapevine Clones Are Related to Their Cluster Compactness, Fruitfulness, and Berry Size

Abstract

Grapevine cluster compactness has a clear impact on fruit quality and health status, as clusters with greater compactness are more susceptible to pests and diseases and ripen more asynchronously. Different parameters related to inflorescence and cluster architecture (length, width, branching, etc.), fruitfulness (number of berries, number of seeds) and berry size (length, width) contribute to the final level of compactness. From a collection of 501 clones of cultivar Garnacha Tinta, two compact and two loose clones with stable differences for cluster compactness-related traits were selected and phenotyped. Key organs and developmental stages were selected for sampling and transcriptomic analyses. Comparison of global gene expression patterns in flowers at the end of bloom allowed identification of potential gene networks with a role in determining the final berry number, berry size and ultimately cluster compactness. A large portion of the differentially expressed genes were found in networks related to cell division (carbohydrates uptake, cell wall metabolism, cell cycle, nucleic acids metabolism, cell division, DNA repair). Their greater expression level in flowers of compact clones indicated that the number of berries and the berry size at ripening appear related to the rate of cell replication in flowers during the early growth stages after pollination. In addition, fluctuations in auxin and gibberellin signaling and transport related gene expression support that they play a central role in fruit set and impact berry number and size. Other hormones, such as ethylene and jasmonate may differentially regulate indirect effects, such as defense mechanisms activation or polyphenols production. This is the first transcriptomic based analysis focused on the discovery of the underlying gene networks involved in grapevine traits of grapevine cluster compactness, berry number and berry size.

A double-sigmoid model for grapevine bunch compactness development

“…As a result, bunch compactness is becoming an important trait for clonal selection and grapevine breeding programs (Blaich et al, 2007;Regner, 2015), so a better understanding of this trait is needed. Tello et al, 2015) have recently identified three traits (rachis architecture, berry number and berry dimensions) as the main factors affecting bunch compactness variation in a multi-cultivar framework, whose developmental determination is controlled by diverse genetic and metabolic pathways (Deluc et al, 2007;Diaz-Riquelme et al, 2014;Grimplet et al, 2017;Li-Mallet et al, 2016). Differences in rachis architecture between loose and compact cultivars are mainly determined during the period of inflorescence development prior to anthesis (Shavrukov et al, 2004).…”

Same same but different: Cluster architecture variation in five ‘Pinot Noir’ clonal selection lines correlates with differential expression of three transcription factors and further growth related genes

“…The cluster I genes with down-regulation in loose clusters also encompass VIT_18s0001g04890 , annotated as a sulfate transporter. The two genes, VIT_18s0001g04890 and VIT_18s0001g03160 , have been described to be repressed in ‘Garnacha Tinta’ clones with larger berries (Grimplet et al 2017). This is in line with our results here for ‘Pinot Noir’ clones, as high MBV (mean berry volume) corresponds to large berries, which are an important determinant for loose clusters.…”

“…Intravarietal diversity in cluster architecture sub-traits of grapevine cultivars has been reported in only a few cases, like ‘Garnacha Tinta’, ‘Tempranillo’, ‘Aglianico’ and ‘Muscat of Alexandria’ (Grimplet et al 2019; Grimplet et al 2017). For ‘Albariño’ clones and for ‘Pinot Noir’ clones the studies of Alonso-Villaverde et al (2008) and Konrad et al (2003) proved, that intravarietal cluster architecture variance correlates with the suseptebility to B.cinerea , i.e.…”

Unraveling the transcriptional complexity of compactness in sistan grape cluster

“…Several factors are effective on grape cluster compactness such as number and size of berries and length of peduncle and pedicels. The effective factors in grape cluster compactness have been investigated by microarray technology [46]. Transciptomic comparison for two clones related to Garnacha Tinta cultivar of grape, with different cluster compactness, indicated the high level of cell division in the earliest stages of flower development, plays an important role in the number and size of berries and, consequently, grape cluster compactness.…”