Selection of arbuscular mycorrhizal fungi for sugarcane in four soils with the presence of dark septate endophytes

ABSTRACT. The present study aimed to select efficient arbuscular mycorrhizal fungi (AMF) for sugarcane growth and P nutrition in four soils that spontaneously contained dark septate endophytes (DSE). The effect of nine AMF isolates was evaluated individually in sugarcane presprouted seedlings (SP81-3250) grown under greenhouse conditions for a 120-day period. The isolates that stimulated plant growth in the soils with low P availability were Acaulospora colombiana (ACOL), Claroideoglomus etunicatum (CETU), Gigaspora margarita (GMAR), Rhizophagus clarus (RCLA) and Scutellospora calospora (SCAL). Compared to the Yellow Argisol, which had the highest P level, the Red-Yellow Argisol, with an intermediate P content, increased plant height. Compared to the other treatments, inoculation with ACOL, RCLA, and SCAL resulted in higher foliar P content in plants grown in soils with high to intermediate P levels. Root colonization by AMF and DSE was verified in the plants, with the coexistence of both fungal groups in the same plant and/or root fragment. However, AMF colonization was low compared to DSE colonization. The cooccurrence of DSE and AMF was higher in the plants inoculated with ACOL, RCLA, SCAL, and Dentiscutata heterogama. ACOL, CETU, GMAR, RCLA, and SCAL are AMF isolates that have the potential to establish a mycorrhizal inoculant for sugarcane that would be effective in several soils.

摘要
本研究旨在从4种自然携带深色有隔内生真菌（dark septate endophytes，DSE）的土壤中，筛选可促进甘蔗生长、改善其磷素营养的高效丛枝菌根真菌（arbuscular mycorrhizal fungi，AMF）。试验以预萌发甘蔗幼苗（SP81-3250）为试材，于温室条件下开展为期120天的单独接种试验，共评估9株AMF分离物的效果。
在低磷有效性土壤中可显著促进甘蔗生长的AMF分离物包括哥伦比亚无梗囊霉（Acaulospora colombiana，ACOL）、光亮类球囊霉（Claroideoglomus etunicatum，CETU）、玛瑞加巨孢囊霉（Gigaspora margarita，GMAR）、根内根孢囊霉（Rhizophagus clarus，RCLA）及花被盾孢囊霉（Scutellospora calospora，SCAL）。与磷素水平最高的黄化老成土（Yellow Argisol）相比，磷素含量中等的红化黄化老成土（Red-Yellow Argisol）可使甘蔗株高显著提升。相较于其余接种处理，在高至中等磷水平的土壤中接种ACOL、RCLA与SCAL，可显著提高甘蔗叶片磷含量。
试验证实，甘蔗根系可被AMF与DSE共同定殖，两类真菌可共存于同一植株乃至同一根段内；但AMF定殖率显著低于DSE定殖率。接种ACOL、RCLA、SCAL及异形盾孢囊霉（Dentiscutata heterogama）的甘蔗植株中，DSE与AMF的共存率更高。
ACOL、CETU、GMAR、RCLA与SCAL这5株AMF分离物，具备开发为适配多类土壤的甘蔗菌根接种剂的应用潜力。