Transcriptomic analysis of interstock-induced dwarfism in Sweet Persimmon (Diospyros kaki Thunb.)

Abstract

Growth monitoring indicated that the height of ‘Kanshu’ plants with ‘Nantong-xiaofangshi’ as an interstock was significantly shorter than that of ‘Kanshu’ plants with no interstock. A transcriptome analysis of the two graft combinations (‘Kanshu’/ Diospyros lotus and ‘Kanshu’/‘Nantong-xiaofangshi’/ Diospyros lotus ) was conducted to explore the dwarfing genes related to the use of the ‘Nantong-xiaofangshi’ interstock. Hormone levels and water conductance were also measured in these two graft combinations. The results indicated that the levels of both IAA and GA were lower in ‘Kanshu’ that had been grafted onto the ‘Nantong-xiaofangshi’ interstock than in ‘Kanshu’ with no interstock; additionally, the water conductance was lower in grafts with interstocks than in grafts without interstocks. The expression of AUX/IAA and auxin-responsive GH3 genes was enhanced in scions grafted on the interstock and was negatively correlated with the IAA content and growth of scions. The expression of GA2ox , DELLA , and SPINDLY genes were also upregulated and associated with a decrease in the level of GA in scions grafted on the interstock. Since one of the GA2ox unigenes was annotated as DkGA2ox1 in Diospyros kaki , but was not functionally validated, a functional analysis was conducted in transgenic tobacco. Overexpression of DkGA2ox1 in transgenic plants resulted in a dwarf phenotype that could be recovered by the exogenous application of GA 3 . We conclude that the ‘Nantong-xiaofangshi’ interstock affects the water conductance and expression of genes related to the metabolism and transduction of IAA and GA in the grafted scion and thus regulates phytohormone levels, producing dwarfing.

Expression of Gibberellin Metabolism Genes and Signalling Components in Dwarf Phenotype of Breadfruit (Artocarpus altilis) Plants Growing on Marang (Artocarpus odoratissimus) Rootstocks

“…Of the two GA catabolic genes, AaGA2ox1 and AaGA2ox2, a more consistent increase in the transcript levels of the major gene, AaGA2ox1, in the period suggests an upregulation of GA deactivation in scion stems on marang rootstocks in this period (Figure 2). Upregulation of a GA2ox gene accompanying a decreased GA level was previously reported in scions of persimmon trees grafted on dwarfing interstocks [15]. Overexpression of GA2ox enhances GA deactivation and produces dwarf phenotype in many species [16,17,21].…”

“…In ungrafted apple rootstocks, the level of GAs is the lowest in the dwarfing rootstock M.9 and the highest in the non-dwarfing rootstock MM111 [13]. Transcriptomic analysis revealed downregulation of GA biosynthetic genes in scions of apple trees gowning on dwarfing rootstocks [14] and upregulation of a GA catabolic gene together with decreased GA level in persimmon scion stems grafted on dwarfing interstocks [15]. Furthermore, a dwarf plum hybrid with elevated transcript levels of a major GA catabolic gene, GA2ox, exhibits shorter internodes and reduced stem elongation, and when used as rootstocks, it reduces the level of bioactive GAs in scions and reduces scion vigor [16].…”

Antioxidant and the Dwarfing Candidate Gene of “Nantongxiaofangshi” (Diospyros kaki Thunb.)

“…In the present study, two-year-old “Nantongxiaofangshi” and “Dafangshi” scions grafted on “Junqianzi” rootstocks were obtained from the Fruit Tree Biotechnology Laboratory, Nanjing, China. The leaves sampled from “Nantongxiaofangshi” were taken at the leaf-expanding stage (2018.4.18), the terminal bud senescence stage (2018.5.10), the flowering stage (2018.5.22), the physiological fruit drop stage (2018.6.11), and the fruit color development stage (2018.9.13) [20]. All chemicals used in the present work were purchased from Beijing Solarbio Science and Technology Company Limited (Beijing, China).…”

“…Deguchi et al have reported that a cDNA encoding sorbitol-6-phosphate dehydrogenase (S6PDH) of sorbitol biosynthesis from rosaceae was introduced into the Japanese persimmon ( Diospyros kaki ) to increase the environmental stress tolerance and exhibited dwarfing phenotypes [19]. According to our previous research reported, the “Nantongxiaofangshi” interstock has superior characteristic compared to the nongrafted persimmon trees [20]. Academic researches have mainly conducted on fruit trees, such as apple [21], pear [22], and citrus [23].…”

The Impact of Metabolic Scion–Rootstock Interactions in Different Grapevine Tissues and Phloem Exudates

“…Nevertheless, it must be taken into account that only relative quantification of the phloem sap can be performed since it is an exudation rather than a direct collection of the phloem sap [18]. New omics approaches have recently been applied in grafting studies to dissect the molecular mechanisms of the early graft-junction formation [20], to unveil the phenomenon of graft compatibility [21][22][23], and to understand the scion-rootstock interactions leading to the alteration of agronomically important traits [24][25][26]. Metabolites, as the end-product of gene expression and regulation, have also been investigated in grafted grapevine [27] and citrus trees [17] and were associated to graft formation and fruit quality.…”