TY - JOUR
T1 - Enhanced Secondary- and Hormone Metabolism in Leaves of Arbuscular Mycorrhizal Medicago truncatula
AU - Adolfsson, Lisa
AU - Nziengui, Hugues
AU - Abreu, Ilka N.
AU - Simura, Jan
AU - Beebo, Azeez
AU - Herdean, Andrei
AU - Aboalizadeh, Jila
AU - Siroka, Jitka
AU - Moritz, Thomas
AU - Novak, Ondrej
AU - Ljung, Karin
AU - Schoefs, Benoit
AU - Spetea, Cornelia
PY - 2017/9
Y1 - 2017/9
N2 - Arbuscular mycorrhizas (AM) are the most common symbiotic associations between a plant’s root compartment and fungi. They provide nutritional benefit (mostly inorganic phosphate [Pi ]), leading to improved growth, and nonnutritional benefits, including defense responses to environmental cues throughout the host plant, which, in return, delivers carbohydrates to the symbiont. However, how transcriptional and metabolic changes occurring in leaves of AM plants differ from those induced by P fertilization is poorly understood. We investigated systemic changes in the leaves of mycorrhized Medicago truncatula ini conditions with no improved Pi status and compared them with those induced by high-Pi treatment in nonmycorrhized plants. Microarray-based genome-wide profiling indicated up-regulation by mycorrhization of genes involved in flavonoid, terpenoid, jasmonic acid (JA), and abscisic acid (ABA) biosynthesis as well as enhanced expression of MYC2, the master regulator of JA-dependent responses. Accordingly, total anthocyanins and flavonoids increased, and most flavonoid species were enriched in AM leaves. Both the AM and Pi treatments corepressed iron homeostasis genes, resulting in lower levels of available iron in leaves. In addition, higher levels of cytokinins were found in leaves of AM- and Pi-treated plants, whereas the level of ABA was increased specifically in AM leaves. Foliar treatment of nonmycorrhized plants with either ABA or JA induced the up-regulation of MYC2, but only JA also induced the up-regulation of flavonoid and terpenoid biosynthetic genes. Based on these results, we propose that mycorrhization and Pi fertilization share cytokinin-mediated improved shoot growth, whereas enhanced ABA biosynthesis and JA-regulated flavonoid and terpenoid biosynthesis in leaves are specific to mycorrhization.
AB - Arbuscular mycorrhizas (AM) are the most common symbiotic associations between a plant’s root compartment and fungi. They provide nutritional benefit (mostly inorganic phosphate [Pi ]), leading to improved growth, and nonnutritional benefits, including defense responses to environmental cues throughout the host plant, which, in return, delivers carbohydrates to the symbiont. However, how transcriptional and metabolic changes occurring in leaves of AM plants differ from those induced by P fertilization is poorly understood. We investigated systemic changes in the leaves of mycorrhized Medicago truncatula ini conditions with no improved Pi status and compared them with those induced by high-Pi treatment in nonmycorrhized plants. Microarray-based genome-wide profiling indicated up-regulation by mycorrhization of genes involved in flavonoid, terpenoid, jasmonic acid (JA), and abscisic acid (ABA) biosynthesis as well as enhanced expression of MYC2, the master regulator of JA-dependent responses. Accordingly, total anthocyanins and flavonoids increased, and most flavonoid species were enriched in AM leaves. Both the AM and Pi treatments corepressed iron homeostasis genes, resulting in lower levels of available iron in leaves. In addition, higher levels of cytokinins were found in leaves of AM- and Pi-treated plants, whereas the level of ABA was increased specifically in AM leaves. Foliar treatment of nonmycorrhized plants with either ABA or JA induced the up-regulation of MYC2, but only JA also induced the up-regulation of flavonoid and terpenoid biosynthetic genes. Based on these results, we propose that mycorrhization and Pi fertilization share cytokinin-mediated improved shoot growth, whereas enhanced ABA biosynthesis and JA-regulated flavonoid and terpenoid biosynthesis in leaves are specific to mycorrhization.
U2 - 10.1104/pp.16.01509
DO - 10.1104/pp.16.01509
M3 - Journal article
C2 - 28698354
SN - 0032-0889
VL - 175
SP - 392
EP - 411
JO - Plant Physiology
JF - Plant Physiology
IS - 1
ER -