Global climate change and anthropological activities have led to a decline in insect pollinators worldwide. Agricultural globalisation and intensification have also removed crops from their natural insect pollinators, and sparked research to identify alternate natural insect pollinators and artificial technologies. In certain countries such as Australia the importation of commercial insect pollinators is prohibited, necessitating manual labour to stimulate floral pollination. Artificial pollination technologies are now increasingly essential as the demand for food grown in protected facilities increases worldwide. For tomato fruits, precision pollination has the ability to vastly improve their seed set, size, yield, and quality under optimal environmental conditions and has become financially beneficial. Like many crops from the Solanaceae, tomatoes have a unique self-pollinating mechanism that requires stimulation of the floral organs to release pollen from the poricidal anthers. This review investigates various mechanisms employed to pollinate tomato flowers and discusses emerging precision pollination technologies. The advantages and disadvantages of various pollinating technologies currently available in the protected-cropping industry are described. We provide a buzz perspective on new promising pollination technologies involving robotic air and acoustic devices that are still in their nascency and could provide non-contact techniques to automate pollination for the tomato horticultural industry.

Carotenoids are secondary metabolites synthesized in plastids that function in photosynthesis, photoprotection, growth and development of plants. Carotenoids contribute to the yellowish, orange and pinkish-red hues of leaves, flowers and fruits, as well as various aromas. They provide substrates for the biosynthesis of phytohormones and are cleavable into smaller apocarotenoids that function as retrograde signals and/or mediate intracellular communication as well as regulate gene transcription and/or protein translation. Carotenoid biosynthesis and gene regulation are tightly coordinated with tissue-specific plastid differentiation, seedling morphogenesis, fruit development, and prevailing environmental growth conditions such as light, temperature and mycorrhizal interactions. In the last decade, epigenetic processes have been linked to the regulation of carotenoid biosynthesis, accumulation and degradation during plant development. Next-generation sequencing approaches have shed new light on key rate-limiting steps in carotenoid pathways targeted by epigenetic modifications that synchronize carotenoid accumulation with plastid development and morphogenesis. We discuss how histone modifications (methylation and acetylation), DNA methylation and demethylation, as well as small RNA gene silencing processes can modulate carotenoid biosynthesis, accumulation and apocarotenoid generation throughout the plants’ life cycle: from seed germination to fruit morphogenesis. This review highlights how apocarotenoid signals regulate plastid biogenesis and gene expression in sync with chromatin alterations during skotomorphogenesis and photo-morphogenesis. We provide a new perspective based upon emerging evidence that supports a likely role for carotenoids in contributing to the programming and/or maintenance of the plants' epigenetic landscape.

Artificial pollination methods rely primarily on air-jets, vibrating wands and trellis tapping which can spread pathogens. This problem can be addressed by non-contact sonic techniques that vibrate cells via sound waves yet how frequency and intensity affect pollination, seed set and fruit size remain unclear. Our study systematic characterizes frequency-dependent vibration events on greenhouse-grown tomato flowers comparing them with contact-induced oscillations from a vibrating wand and a mechanical shaker arm. Sonic vibrations in the frequency range from 50 to 10,000 Hz increased pollination, fruit size, weight, and seed set in Sweetelle and Endeavour commercial varieties. Scanning electron microscopy revealed sonication loosened the trichomes joining the poricidal cone lobes that encase the anthers filled with pollen. Ultra-sonic frequencies enlarged fruit size, whereas seed set remained constant thereby challenging the floral cells power-law rheological characteristics in different frequency scales. Our bioacoustics non-contact precision technology can be used to boost tomato floral self-pollination. Teaser Leveraging bioacoustics from bees and bats to boost precision pollination of tomato flowers and fruit size in commercial varieties

Heirloom golden tomato fruit varieties are highly nutritious as they accumulate tetra- cis -lycopene, which has a higher bioavailability and recognised health benefits in treating anti-inflammatory diseases compared to all- trans -lycopene isomers found in red tomatoes. We investigated if photoisomerization of tetra- cis -lycopene occurs in roots of the golden tangerine Micro-Tom variety ( tang ^mic ), and how this affects root to shoot biomass, mycorrhizal colonization, abscisic acid accumulation, and responses to drought. tang ^mic plants grown in soil under glasshouse conditions displayed a reduction in height, number of flowers, fruit yield, and root length compared to wild type (WT). Soil inoculation with Rhizophagus irregularis revealed fewer arbuscules and other fungal structures in the endodermal cells of roots in tang ^mic relative to WT. The roots of tang ^mic hyperaccumulated acyclic cis -carotenes, while only trace levels of xanthophylls and abscisic acid were detected. In response to a water deficit, leaves from the tang ^mic plants displayed a rapid decline in maximum quantum yield of photosystem II compared to WT, indicating a defective root to shoot signalling response to drought. The lack of xanthophylls biosynthesis in tang ^mic roots reduced abscisic acid levels, thereby likely impairing endomycorrhiza colonisation and drought-induced root to shoot signalling. Research Highlights: Photoisomerization of prolycopene to lycopene is limited in root plastids. Roots of tangerine reveal an important tissue sink to store micronutrients such as prolycopene. Roots of tangerine lack ABA and show impaired mycorrhizal colonization. The tangerine plant is drought sensitive and has a smaller biomass as well as reduced yield.