Yuan Jie, Shi Kun, Zhou Xiaoyue, Wang Lei, Xu Cong, Zhang Hui, Zhu Guopeng, Si Chengcheng, Wang Jidong, Zhang Yongchun
Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China.
National Agricultural Experimental Station for Agricultural Envrionment, Nanjing, Jiangsu, China.
Front Microbiol. 2023 Jan 9;13:1075957. doi: 10.3389/fmicb.2022.1075957. eCollection 2022.
Sweet potato is a typical "potassium (K)-favoring" food crop and strongly dependent on arbuscular mycorrhizal fungi (AMF). Recent studies show the importance of K and AMF to morphology optimization and nutrient uptake regulation of sweet potato; meanwhile, the interaction exists between K and K use efficiency (KIUE) in sweet potato. To date, only a few studies have shown that AMF can improve plant K nutrition, and whether the benefits conferred by AMF on plant are related to K remains unclear. In this study, low-KIUE genotype "N1" and high-KIUE genotype "Xu28" were used as experimental sweet potato; (FM) and (CE) were used as experimental AMF. In a pot experiment, plants "N1" and "Xu28" were inoculated with FM or CE, and applied with or without K fertilizer to uncover the effects of K application and AMF inoculation on the root morphology and nutrient absorption of sweet potato during their growing period. Results demonstrated that AMF inoculation-improved root morphology of sweet potato highly relied on K application. With K application, AMF inoculation significantly increased root tip number of "N1" in the swelling stage and optimized multiple root morphological indexes (total root length, root surface area, root volume, root diameter, root branch number, and root tip number) of "Xu28" and CE had the best optimization effect on the root morphology of "Xu28". In addition, CE inoculation significantly promoted root dry matter accumulation of "Xu28" in the swelling and harvesting stages, coordinated aerial part and root growth of "Xu28", reduced the dry matter to leaf and petiole, and was beneficial to dry matter allocation to the root under conditions of K supply. Another promising finding was that CE inoculation could limit K allocation to the aboveground and promote root K accumulation of "Xu28" under the condition with K application. The above results lead to the conclusion that K and CE displayed a synergistic effect on root development and K acquisition of high-KIUE "Xu28". This study could provide a theoretical basis for more scientific application of AMF in sweet potato cultivation and will help further clarify the outcomes of plant-K-AMF interactions.
甘薯是典型的“喜钾”粮食作物，对丛枝菌根真菌（AMF）高度依赖。近期研究表明钾和AMF对甘薯形态优化及养分吸收调控具有重要作用；同时，甘薯体内钾与钾利用效率（KIUE）之间存在相互作用。迄今为止，仅有少数研究表明AMF可改善植物钾营养，而AMF赋予植物的益处是否与钾有关尚不清楚。本研究以低钾利用效率基因型“N1”和高钾利用效率基因型“Xu28”作为试验甘薯品种；以摩西斗管囊霉（FM）和幼套球囊霉（CE）作为试验AMF。在盆栽试验中，对“N1”和“Xu28”植株接种FM或CE，并施加或不施加钾肥，以揭示施钾和接种AMF对甘薯生长期间根系形态和养分吸收的影响。结果表明，接种AMF对甘薯根系形态的改善高度依赖于施钾。施钾条件下，接种AMF显著增加了“N1”在膨大期的根尖数量，并优化了“Xu28”的多个根系形态指标（总根长、根表面积、根体积、根直径、根分支数和根尖数），且CE对“Xu28”根系形态的优化效果最佳。此外，接种CE显著促进了“Xu28”在膨大期和收获期的根系干物质积累，协调了“Xu28”地上部与根系的生长，减少了叶片和叶柄的干物质占比，有利于在钾供应条件下将干物质分配到根系。另一个有意义的发现是，在施钾条件下，接种CE可限制钾向地上部的分配，并促进“Xu28”根系钾的积累。上述结果得出结论：钾和CE对高钾利用效率的“Xu28”根系发育和钾吸收表现出协同效应。本研究可为AMF在甘薯栽培中的更科学应用提供理论依据，并有助于进一步阐明植物-钾-AMF相互作用的结果。
