ASHS 2024 Conference

Freezing temperatures can harm peaches in late spring with advanced flowering due to climate change and consequently reduce their yield. Flowering delay is a prominent strategy employed to avoid such spring frost damage. Our previous study demonstrated that treatment with 5% sodium alginate 100 mM CaCl 2 (5AG) can delay the blooming, potentially avoiding frost damage. To elucidate the precise mechanism of flowering delay induced by 5AG in peaches, this study systematically and experimentally analyzed the changes of amino acid profiles in control and 5AG-treated peach plants at different day intervals (0, 1, 2, 11, 21, 25, and 28 DAT). Our findings revealed that the levels of arginine (Arg), glutamate (Glu), and proline (Pro) differed significantly between control and 5AG- treated peach shoots throughout the phenological development of flower buds. Furthermore, Arg and Glu amino acids, are involved in the Pro pathway. Computational metabolomics analyses identified the Pro metabolism related genes and their attributes, gene ontology, gene synteny and gene organizations, which represent diverse biological function of these genes, including flowering responses. In addition, qRT-PCR analysis results revealed that elevated expression of P5CS and P5CR genes, involved in Pro metabolism, led to increased Pro content in control plants. Conversely, 5AG treatment downregulated these genes, resulting in lower proline content. This result suggests that 5AG treatment may restrain gene expression related to Pro accumulation, thereby controlling Pro biosynthesis. In addition, our findings unveiled a direct connection between Pro content reduction and delayed flowering. Taken together, these results provide strong evidence that 5AG treatment significantly delays flowering by controlling Pro metabolisms in Prunus persica.