Manipulating oxygen-dependent ethylene signalling in fruit to reduce food loss

减少粮食损失和浪费对于确保粮食安全以及实现联合国可持续发展目标12.3和Sainsburys Supermarkets Plc可持续发展目标至关重要。气调贮藏被广泛用于延缓果实的成熟和衰老。它包括在储存期间降低新鲜农产品周围大气中的氧气浓度和增加二氧化碳水平（Falagan和Terry 2018）。然而，气体环境的突然变化被视为非生物胁迫，对质量产生负面影响。分级气控（GCA）于2020年被发现，并已被证明可以延长多种新鲜农产品的储存寿命，如蓝莓，葡萄番茄和樱桃。GCA逐渐降低储存气氛中的氧气水平，而不是立即应用最终的CA条件。与对照相比，GCA已被证明可以通过降低疾病发生率来增加蓝莓的储存寿命25%。在冷藏28天后，GCA蓝莓也比CA储存的果实结实27%（Falagan等人，2020年）。GCA与标准CA对储存寿命的改善效果背后的机制尚不清楚，但假设GCA影响氧依赖性乙烯信号传导，即使在非跃变型水果中也是如此。这项工作的目的是从两个角度了解GCA与标准CA相比的作用机制：i）GCA对乙烯敏感性的影响（通过低O2和高CO2分级）;和ii）自然抗病性（通过高CO2）。这项工作将发展了解低氧环境和乙烯生物合成和脱落酸（阿坝）途径之间的关系，在一个动态变化的气体环境。它还将通过显微镜和PCR定量研究真菌病（灰葡萄孢）的进展。

Reducing food loss and waste is essential to ensure food security and in achieving United Nations Sustainable Development Goal 12.3 and Sainsburys Supermarkets Plc sustainability targets. Controlled atmosphere (CA) is broadly used to delay ripening and senescence. It consists of reducing oxygen concentrations and increasing carbon dioxide levels in the atmosphere surrounding fresh produce during storage (Falagan and Terry 2018). However, the sudden change in the gas environment is perceived as an abiotic stress, negatively affecting quality. Graduated Controlled Atmosphere (GCA) was discovered in 2020 and has been shown to extend the storage life of multiple fresh produce types viz. blueberries, vine tomatoes and cherries. GCA gradually reduces oxygen levels in the storage atmosphere rather than instantaneously applying the final CA conditions. GCA has been shown to increase the storage life of blueberries by 25% compared to control by reducing disease incidence when. GCA blueberries were also 27% firmer than CA-stored fruit after 28 days of cold storage (Falagan et al., 2020). The mechanisms behind the improved effect of GCA vs. standard CA on storage life are not known, but it is hypothesized that GCA influences oxygen-dependent ethylene signalling, even in non-climacteric fruit. The aim of the work is to understand the mechanisms by which GCA works compared to standard CA from two perspectives: i) GCA effect on ethylene sensitivity (via low O2 and high CO2 graduation); and ii) natural disease resistance (via high CO2). This work will develop understanding on the relationship between low oxygen environments and the ethylene biosynthesis and abscisic acid (ABA) pathways in a dynamically changing gaseous environment. It will also study the progression of fungal disease (Botrytis cinerea) through microscopy and quantified by PCR.