Zhou Yuchan, Underhill Steven J R
Australian Centre for Pacific Islands Research, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia.
Plants (Basel). 2023 Sep 16;12(18):3285. doi: 10.3390/plants12183285.
Breadfruit () is a traditional fruit tree of 15-30 m height in the tropics. The presence of size-controlling rootstock in the species is not known. A small tropical tree species, lakoocha (), was recently identified as a potential vigor-controlling rootstock, conferring over a 65% reduction in breadfruit tree height. To better understand the intriguing scion/rootstock interactions involved in dwarfing, we investigate flavonoid accumulation and its regulation in breadfruit scions in response to different rootstocks. To this end, we isolated a chalcone synthase cDNA, , and a full-length bifunctional dihydroflavonol 4-reductase cDNA, , from breadfruit scion stems. The expression of both and genes was examined over the period of 16 to 24 months following grafting. During the development of the dwarf phenotype, breadfruit scion stems on lakoocha rootstocks display significant increases in total flavonoid content, and show upregulated expression when compared with those on self-grafts and non-grafts. There is a strong, positive correlation between the transcript levels of and total flavonoid content in scion stems. The transcript levels of are not significantly different across scions on different rootstocks. This work provides insights into the significance of flavonoid biosynthesis in rootstock-induced breadfruit dwarfing.
面包果（）是热带地区一种传统的果树，树高15至30米。该物种中是否存在控制大小的砧木尚不清楚。一种小型热带树种，lakoocha（），最近被确定为一种潜在的控制活力的砧木，能使面包果树的高度降低65%以上。为了更好地理解矮化过程中有趣的接穗/砧木相互作用，我们研究了面包果接穗中黄酮类化合物的积累及其对不同砧木的响应调控。为此，我们从面包果接穗茎中分离出一个查尔酮合酶cDNA，，和一个全长双功能二氢黄酮醇4-还原酶cDNA，。在嫁接后的16至24个月内检测了和基因的表达。在矮化表型发育过程中，lakoocha砧木上的面包果接穗茎总黄酮含量显著增加，与自嫁接和未嫁接的接穗相比，其表达上调。接穗茎中的转录水平与总黄酮含量之间存在很强的正相关。不同砧木上接穗的转录水平没有显著差异。这项工作为黄酮类生物合成在砧木诱导的面包果矮化中的重要性提供了见解。
