Search

Olive (Olea europaea L.) is an important Mediterranean tree species with a longstanding history of cultivation, boasting a diverse array of local cultivars. While traditional olive orchards are valued for their cultural and aesthetic significance, they often face economic sustainability challenges in the modern context. The success of both traditional and newly introduced cultivars (e.g. those obtained by cross-breeding) is hindered by self-incompatibility, a prevalent issue for this species that results in low fruit set when limited genetic diversity is present. Further, biological, environmental, and agronomic factors have been shown to interlink in shaping fertilization patterns, hence impacting on the final yield. Climatic conditions during pollination, such as excessive rainfall or high temperatures, can further exacerbate the problem. In this work, we provide an overview of the various factors that trigger the phenomenon of suboptimal fruit set in olive trees. This work provides a comprehensive understanding of the interplay among these factors, shedding light on potential mechanisms and pathways that contribute to the observed outcomes in the context of self-incompatibility in olive. [ABSTRACT FROM AUTHOR]

Introgression of genetic resistance to fungal diseases from American and Asian Vitis species traditionally pursued in grape breeding programs, although facilitated by molecular tools, has an impact on wine quality that still slows down development of competitive varieties. A contribution to the genetic improvement of grapevines for resistance to pathogens may come from unexplored genetic resources of the Eurasian Vitis vinifera L. In the present study, a hundred grapevine accessions from Georgia, Armenia and Azerbaijan were genotyped with SSR markers linked to QTLs for resistance to downy and powdery mildew, and with 21 SSR markers widely used for genetic diversity and relationship analysis. Looking at population genetic structure, Armenian and Azerbaijani accessions fell within the same cluster and were included among the Central Asian grape varieties of a homogeneous dataset, while Georgian accessions formed a separate group. Pattern of SSR alleles flanking the locus Ren1 and associated with resistance to Erysiphe necator in 'Kishmish vatkana', 'Dzhandzhal kara' and other Central Asian cultivars were found in three varieties from the Azerbaijani population that reached very high scores when assessed for PM resistance.

Rising temperatures and ozone levels are among the most striking stressful phenomena of global climate changes, and they threaten plants that are unable to react rapidly and efficiently. Generic responses of plants to stresses include the production of excess reactive oxygen species (ROS). Excessive ROS accumulation can lead to extensive oxidation of important components such as nucleic acids, proteins and lipids which can further exacerbate ROS accumulation leading to programmed cell death. Although most studies on plant antioxidants have focused on non-volatile compounds, volatiles belonging to the isoprenoid family have been implicated in the protection against abiotic stresses, in particular thermal and oxidative stress whose frequency and extent is being exacerbated by ongoing global change and anthropogenic pollution. Historically, research has focused on isoprene, demonstrating that isoprene-emitting plants are more tolerant to ozone exposure and heat stress, reducing ROS accumulation. Yet, evidence is being compiled that shows other volatile isoprenoids may be involved in plant responses against abiotic stresses. Grapevines are not isoprene emitters but some varieties produce other volatile isoprenoids such as monoterpenes. We investigated photosynthesis and emission of volatile organic compounds upon heat stress in two Vitis vinifera cv. ‘Chardonnay’ clones differing only for a mutation in the DXS gene (2-C-methyl-D-erythritol 4-phosphate (MEP) pathway), regulating volatile isoprenoid biosynthesis. We showed that the mutation led to a strong increase in monoterpene emission upon heat stress. At the same time, maximum photochemical quantum yield (Fv/Fm ratio) of PSII was affected by the stress in the non-emitting clone while the monoterpene emitter showed a significant resilience, thus indicating a possible antioxidant role of monoterpenes in grapevine. Future mechanistic studies should focus on unveiling the actual mechanism responsible for such findings.

Plant biotechnologies have demonstrated to be a resource to cope with world population growth and environmental sustainability by increasing yield and partially reducing reliance upon agrochemicals. Nevertheless, despite several nutritionally enhanced crops have been obtained through genetic manipulation, their deployment in agriculture – to date – still remains marginal. In this article, we discuss the different GM approaches effectively employed to produce nutritionally improved food crops, as well as the future perspectives to overcome the barriers preventing the wide cultivation/commercialization of these products. [ABSTRACT FROM AUTHOR]