Methyl jasmonate root secretion improves low phosphorus tolerance in apple rootstock

Figure.A model of LP-sensitive and LP-tolerant apple rootstocks grown under LP conditions, adapted from et al. 2025.In LP-sensitive rootstocks (left), expression of MdHB52 is mediated by MYB transcription factors under LP conditions.MdHB52 represses MeJA biosynthetic genes MdAOS3 and MdOPR2 and leads to a lower MeJA synthesis and secretion from roots.In LP-tolerant rootstocks (right), MdHB52 expression is repressed due to an SNP variation in the promoter region and, as a consequence, promotes expression of MdAOS3 and MdOPR2 and increases MeJA synthesis and its secretion from roots.This in turn leads to increased P absorption under LP conditions.Hexagons represent MeJA, spheres represent plant-available P, and two combined spheres represent plant-unavailable or insoluble P in the soil.