Correction: Liu et al. Epichloë gansuensis Increases the Tolerance of Achnatherum inebrians to Low-P Stress by Modulating Amino Acids Metabolism and Phosphorus Utilization Efficiency. J. Fungi 2021, 7, 390

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Epichloë gansuensis Increases the Tolerance of Achnatherum inebrians to Low-P Stress by Modulating Amino Acids Metabolism and Phosphorus Utilization Efficiency

In the long-term evolutionary process, Achnatherum inebrians and seed-borne endophytic fungi, Epichloë gansuensis, formed a mutually beneficial symbiosis relationship, and Epichloë gansuensis has an important biological role in improving the tolerance of host grasses to abiotic stress. In this work, we first assessed the effects of Epichloë gansuensis on dry weight, the content of C, N, P and metal ions, and metabolic pathway of amino acids, and phosphorus utilization efficiency (PUE) of Achnatherum inebrians at low P stress. Our results showed that the dry weights, the content of alanine, arginine, aspartic acid, glycine, glutamine, glutamic acid, L-asparagine, lysine, phenylalanine, proline, serine, threonine, and tryptophan were higher in leaves of Epichloë gansuensis-infected (E+) Achnatherum inebrians than Epichloë gansuensis-uninfected (E−) Achnatherum inebrians at low P stress. Further, Epichloë gansuensis increased C content of roots compared to the root of E− plant at 0.01 mM P and 0.5 mM P; Epichloë gansuensis increased K content of leaves compared to the leaf of E− plant at 0.01 mM P and 0.5 mM P. Epichloë gansuensis reduced Ca content of roots compared to the root of E− plant at 0.01 mM P and 0.5 mM P; Epichloë gansuensis reduced the content of Mg and Fe in leaves compared to the leaf of E− plant at 0.01 mM P and 0.5 mM P. In addition, at low P stress, Epichloë gansuensis most probably influenced aspartate and glutamate metabolism; valine, leucine, and isoleucine biosynthesis in leaves; and arginine and proline metabolism; alanine, aspartate, and glutamate metabolism in roots. Epichloë gansuensis also affected the content of organic acid and stress-related metabolites at low P stress. In conclusion, Epichloë gansuensis improves Achnatherum inebrians growth at low P stress by regulating the metabolic pathway of amino acids, amino acids content, organic acid content, and increasing PUE.

miR399-UBC24 module enhances freezing tolerance through regulating CBF signaling pathway and starch degradation

Although the regulation in Pi homeostasis of miR399 have been studied in various plants, its molecular mechanisms in response to freezing stress are still elusive. In this work, we found that the expression of tae-miR399 and its target gene TaUBC24 in tillering nodes of strong cold resistance winter wheat cultivar Dongnongdongmai1 (Dn1) was significantly altered subjected to severe winter. tae-miR399 and its target gene TaUBC24 were also responsive to short-term freezing stress in tillering nodes of Dn1 seedlings. TaUBC24 physically interacted with TaICE1. Ehanced freezing tolerance was observed in overexpressing tae-miR399 Arabidopsis lines. Under freezing stress, overexpressing tae-miR399 decreased the expression of AtUBC24 to increase the expression of genes in CBF signaling pathway, Pi translocation pathway and starch metablism, including AtCBFs, AtCOR47, AtCOR413IM, AtPHT1;4, AtAPLs and AtBAMs, inhibit the degradation of AtICE1 and AtPHO1, and promote the activities of SOD, POD and CAT. These findings indicated that the increased freezing tolerance was dependent upon elevating CBF signaling pathway, phosphorus utilization efficiency, starch degradation, accumulation of soluble sugar and ability of ROS scavenge. These results will aid our understanding of molecular mechanism of how miR399-UBC24 module plays a cardinal role in regulating plant freezing stress tolerance through mediating the downstream pathways.

Impact of Mycorrhization on Phosphorus Utilization Efficiency of Acacia gummifera and Retama monosperma under Salt Stress

The impact of salt stress on the growth and phosphorus utilization efficiency (PUE) of two leguminous species: Retama monosperma and Acacia gummifera was studied. The effectiveness of arbuscular mycorrhizal fungi (AMF) to mitigate salt stress was furthermore assessed. Growth, N and P tissue concentrations, mycorrhizal root colonization frequency and intensity, and P utilization efficiency (PUE) in the absence or presence of AMF were evaluated under no salt (0 mM L−1) and three salt (NaCl) concentrations of (25, 50 and 100 mM L−1) using a natural sterilized soil. A significant difference in mycorrhizal colonization intensity, root-to-shoot ratio, P uptake, PUE, and N uptake was observed between the legume species. Salt stress inhibited the shoot and root growth, and reduced P and N uptake by the legume species. Mycorrhizal inoculation aided to mitigate the effects of salt stress with an average increase of shoot and root growth responses by 35% and 32% in the inoculated than in the non-inoculated A. gummifera treatments. The average shoot and root growth responses were 37% and 45% higher in the inoculated compared to the non-inoculated treatments of R. monosperma. Average mycorrhizal shoot and root P uptake responses were 66% and 68% under A. gummifera, and 40% and 95% under R. monosperma, respectively. Mycorrhizal inoculated treatments consistently maintained lower PUE in the roots. The results provide insights for further investigations on the AMF conferred mechanisms to salt stress tolerance response by A. gummifera and R. monosperma, to enable the development of effective technologies for sustainable afforestation and reforestation programs in the Atlantic coast of Morocco.

Expression of OsPSTOL1 Improves the Phosphorus Utilization Efficiency of Transgenic Populus tomentosa

OsPSTOL1encodesa phosphorus (P) deficiency-tolerant protein expressed in the ausrice variety, Kasalash, which functions by enhancing the ability of the plant to obtain P and other nutrients; however, its role in woody plants remains unknown. In the present study, we isolated OsPSTOL1from Oryza sativa L. and subsequently generated OsPSTOL1-overexpressing transgenic Populus tomentosa. It was found that in the state of P deficiency, the transgenic P. tomentosahad a greater root length, the symptoms of P-deficiencyappeared much later, and the total nitrogen (TN) and phosphorus (TP) content was higher as compared with that of wild type plants. Upregulation of P-tolerance genes in transgenic P. tomentosaunder P-deficient conditions was analyzed by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR),the results of which were consistent with the physiological traits. In summary, these findings show thatOsPSTOL1 plays a positive role in the regulation of P uptake and utilization in transgenicP. tomentosatrees under P-deficient conditions and provide evidence for the potential application of OsPSTOL1in woody plants to overcome soil P deficiency.© 2021 Friends Science Publishers