Gene Expression in 1-Methylcyclopropene (1-MCP) Treated Tomatoes during Pre-Climacteric Ripening Suggests Shared Regulation of Methionine Biosynthesis, Ethylene Production and Respiration

Abstract

The physiology of fruit ripening is defined as either ‘climacteric’ or ‘non-climacteric’. In climacteric fruit respiration during ripening increases until it reaches a peak, which is accompanied by an increase in autocatalytic ethylene production, whereas the respiration of non-climacteric fruit does not increase and they have no requirement for ethylene to complete their ripening. In an attempt to gain further insight into the involvement of autocatalytic ethylene production with the climacteric rise in respiration, tomato fruit were harvested at three defined stages of maturity prior to the climacteric peak (mature green, breaker, and early orange) and immediately exposed to the gaseous molecule 1-methylcyclopropene (1-MCP). The gene expression profile at each of these stages was monitored after 24 h, using an Affymetrix tomato microarray chip. This approach enabled us to identify ethylene responsive genes that are commonly regulated at early stages of ripening, as well as new candidate genes. In addition, 1-MCP treatment affected the levels of metabolites related to methionine biosynthesis. Methionine feeds climacteric ethylene production and we found that promotors of the genes of enzymes that catalyze the production of homoserine and homocysteine (aspartokinase/homoserine dehydrogenases and cystathionine beta lyase, respectively), precursors in the methionine pathway, contain the AtSR1 binding motif. This binding motif is recognized by ethylene activated transcription factors, hence indicating a role for ethylene in methionine synthesis during early ripening, explaining the autocatalytic ethylene production during subsequent ripening stages.

Effects of 1‐MCP treatment on volatile compounds and quality in Xiaobai apricot during storage at low temperature

“…In recent studies, 1-MCP has been applied to "Kinnow" mandarin , plums (Larrigaudière et al, 2009), banana (Zhu et al, 2015), tomato (Gamrasni et al, 2020), kiwifruit (Deng et al, 2013), pear (Mahajan et al, 2010), and blueberry (Chiabrando & Giacalone, 2011). However, 1-MCP can negatively impact volatile biosynthesis.…”

Integration of text mining and biological network analysis: Identification of essential genes in sulfate-reducing bacteria

“…On a broader aspect, amino acid metabolism pathways are essential for the survival of organisms because it coined itself as the building block for proteins and enzymes. In OA G20, from the interaction network, we observed that cystathionine beta-lyase (dde_0726) was enriched, which catalyzes the production of homocysteine, a direct precursor metabolite for the formation of methionine ( Gamrasni et al, 2020 ). Parallelly, methionine synthase (dde_2115) was also enriched, which is a vital enzyme in the intermediate step of methionine synthesis ( Ekstrom et al, 2003 ).…”

Effects of Exogenous Ethylene and Cobalt Chloride on Root Growth of Chinese Fir Seedlings under Phosphorus-Deficient Conditions

“…Among these antioxidant enzymes, SOD is a natural superoxide radical scavenging enzyme in cells that can convert unstable O 2− into H 2 O 2 , and POD can convert the H 2 O 2 produced by the SOD disproportionation reaction into non-toxic H 2 O [32]. Moreover, H 2 O 2 is an intermediate in the pathway of ethylene synthesis from methionine, and O 2− is related to the activity of ethylene synthase; hence, CoCl 2 may affect the production of endogenous ethylene by regulating the production of ROS in response to the P-stress conditions of fir [33]. Therefore, CoCl 2 plays an important role in the remodeling of plant roots, thereby prompting plants to respond to the P starvation environment and improving the seedlings' tolerance to P-deficient conditions.…”