Forms of nitrogen uptake, translocation, and transfer via arbuscular mycorrhizal fungi: A review

Abstract

Arbuscular mycorrhizal (AM) fungi are obligate symbionts that colonize the roots of more than 80% of land plants. Experiments on the relationship between the host plant and AM in soil or in sterile root-organ culture have provided clear evidence that the extraradical mycelia of AM fungi uptake various forms of nitrogen (N) and transport the assimilated N to the roots of the host plant. However, the uptake mechanisms of various forms of N and its translocation and transfer from the fungus to the host are virtually unknown. Therefore, there is a dearth of integrated models describing the movement of N through the AM fungal hyphae. Recent studies examined Ri T-DNA-transformed carrot roots colonized with AM fungi in 15 N tracer experiments. In these experiments, the activities of key enzymes were determined, and expressions of genes related to N assimilation and translocation pathways were quantified. This review summarizes and discusses the results of recent research on the forms of N uptake, transport, degradation, and transfer to the roots of the host plant and the underlying mechanisms, as well as research on the forms of N and carbon used by germinating spores and their effects on amino acid metabolism. Finally, a pathway model summarizing the entire mechanism of N metabolism in AM fungi is outlined.

Physiological Responses and Gene Co-Expression Network of Mycorrhizal Roots under K+ Deprivation

“…The improvement of plant nutrition through AM symbiosis and the molecular basis of nutrient transfer are well characterized for phosphorus, nitrogen, and sulfur (Govindarajulu et al, 2005;Javot et al, 2007;Jin et al, 2012;Casieri et al, 2013;Courty et al, 2016;Garcia et al, 2016). However, the role of mycorrhizal symbioses in plant K + nutrition is still understudied and misunderstood .…”

Autecology of Cephalaria taurica Szabó, A Narrow Endemic from Turkey: Plant-Soil Interactions

“…In addition, mycorrhizal fungal activity enhances N uptake and its translocation by acquiring nitrate(NO 3 -), ammonium (NH 4 + ) and amino acids for its host species [26][27][28]. Therefore, availability of required N by C. taurica from nitrogen-poor soil can be explained by either adaptation mechanisms favoring in the way of high accumulation of N or presence of mycorrhizal fungal activity.…”

PENGGUNAAN RHIZOBIUM DAN MIKORIZA UNTUK PERTUMBUHAN Calliandra calothyrsus UNGGUL

“…Rhizobium merupakan bakteri yang mutlak diperlukan untuk nodulasi C. calothyrsus. Sementara mikoriza, merupakan organisme berupa jamur yang akan membantu tanaman untuk mengikat unsur hara pada lokasi tempat unsur-unsur tertentu sulit untuk didapatkan termasuk pada daerah kering dan tanah yang kekurangan hara (Garcia & Zimmermann, 2014;Jin, Liu, & Huang, 2012). Kombinasi penerapan kedua jenis perlakuan ini diharapkan akan membantu C. calothyrsus unggul untuk lebih mengekspresikan keunggulan pertumbuhannya pada berbagai lahan yang ada termasuk lahan yang kurang menguntungkan.…”

“…Keuntungan utama simbiose dengan mikoriza adalah karena kemampuannya menolong tanaman inangnya untuk mendapatkan terutama unsur makro yakni Nitrogen (Jin et al, 2012;Muller et al, 2007), Phosporus (Javot, Pumplin, & Harrison, 2007;Plassard & Dell, 2010) dan Potassium (K+) (Garcia & Zimmermann, 2014) yang sangat dibutuhkan untuk pertumbuhan terutama pada kondisi kekurangan ketersediaan hara tersebut. Mikoriza juga dilaporkan mampu meningkatkan penyerapan unsur Zinc, Cu (Copper) dan Fe, namun terhadap nutrisi mikro tersebut, tanggapannya bisa meningkat, menurun atau tak berdampak (Ajeesh et al, 2015).…”