Molecular mechanisms driving the success of grafting impacted by walnut rootstock
摘要
The foundation for ensuring walnuts of high yield and quality is excellent rootstock. Numerous studies have shown that the walnut rootstock has a major impact on the grafted varieties’ quality, yield, stress resistance, growth, and development. Elucidating the mechanism of grafting affinity in walnuts is crucial, as it paves the way for selecting premium rootstocks to achieve increased production and efficiency. In this study, a combined analysis of the transcriptome, miRNA, and metabolome was conducted to elucidate the molecular mechanisms underlying graft compatibility between different walnut rootstocks (Juglans sigillata cv. ‘Qianhe 7’ and ‘Panzhou’).
ResultsA total of 44, 41, 50, and 28 differential miRNAs were identified between ‘Qianhe 7’ vs ‘Panzhou’ at 1st d, 11th d, 17th d, and 30th d after grafting, respectively. These miRNAs target genes associated with plant hormone signaling pathways, particularly those related to IAA, SA, and ABA, such as ARF, SAUR, and RAS1-like genes. The most dominant metabolites in both J. sigillata rootstocks (cv. ‘Qianhe 7’ and ‘Panzhou’) at 1st d after grafting were salicylic acid (SA) and Indole-3-acetic acid (IAA). The concentration of SA increased with the extension of time in ‘Qianhe 7’, while IAA decreased significantly on the 30th d. The IAA and abscisic acid (ABA) contents of ‘Qianhe 7’ were markedly higher than those observed in ‘Panzhou’ at 11th d and 30th d post-grafting, respectively. But the concentration of jasmonic acid (JA) in the ‘Panzhou’ was significantly higher than that observed in the ‘Qianhe 7’ at 17th d post-grafting.
ConclusionsThese results indicated that SA, ABA, and IAA may play a pivotal role in the adaptability of grafted J. sigillata (‘Qianhe 7’ and ‘Panzhou’), which provides a foundation for understanding walnut graft affinity. A deeper exploration of the synergistic regulatory network between the identified miRNAs and plant hormones is warranted to clarify the underlying mechanisms, thereby informing hormone-based breeding strategies for walnut rootstocks and facilitating the sustainable advancement of the walnut industry.