Transcriptomic comparison of Allium cepa var. agrogatum Don. cultivars with different facilitating potentials on tomato seedlings

ABSTRACT Potato onion has facilitating effect on tomato seedlings; however, the mechanisms underlying the facilitating effect remain unknown. Here, we examined the effects of potato onion leaf volatiles and leachates on tomato seedling growth, and performed a transcriptomic comparison of two potato onion cultivars with different facilitating potentials (‘Suihua’: higher facilitating potential; ‘Qitaihe’: lower facilitating potential). Potato onion leaf volatiles and leachates decreased the stem length, but increased the shoot dry matter of tomato seedlings. Transcriptomic analysis showed that 640 genes were differentially expressed (DEGs) between ‘Suihua’ and ‘Qitaihe.’ DEGs related to photosynthesis, energy metabolism, and hormone metabolism were higher expressed in ‘Suihua’ compared to that in ‘Qitaihe,’ whereas genes related to phenylpropanoid metabolism and disease resistance were lower expressed. Pathway analysis showed the DEGs mainly participated in Metabolism, Biosynthesis of secondary metabolites and Plant hormone signal transduction