Under drought conditions, arbuscular mycorrhizal (AM) fungi may improve plant performance by facilitating the movement of water through extensive hyphal networks. When these networks interconnect neighboring plants in common mycorrhizal networks (CMNs), CMNs are likely to partition water among many individuals. The consequences of CMN-mediated water movement for plant interactions, however, are largely unknown. We set out to examine CMN-mediated interactions among Andropogon gerardii seedlings in a target-plant pot experiment, with watering (watered or long-term drought) and CMN status (intact or severed) as treatments. Intact CMNs improved the survival of seedlings under drought stress and mediated positive, facilitative plant interactions in both watering treatments. Watering increased mycorrhizal colonization rates and improved P uptake, particularly for large individuals. Under drought conditions, improved access to water most likely benefited neighboring plants interacting across CMNs. CMNs appear to have provided the most limiting resource within each treatment, whether P, water, or both, thereby improving survival and growth. Neighbors near large, photosynthate-fixing target plants likely benefited from their establishment of extensive hyphal networks that could access water and dissolved P within soil micropores. In plant communities, CMNs may be vital during drought, which is expected to increase in frequency, intensity, and length with climate change.

• Klíčová slova
• Andropogon gerardii (Big Bluestem), Arbuscular mycorrhizal fungi, Common mycorrhizal networks, Drought, Phosphorus, Plant survival,
• MeSH
• Andropogon * mikrobiologie   fyziologie   MeSH
• fyziologický stres * fyziologie   MeSH
• Kaplanův-Meierův odhad MeSH
• mykorhiza * fyziologie   MeSH
• přežití MeSH
• semenáček * mikrobiologie   fyziologie   MeSH
• voda metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• voda MeSH

Plants are often subjected to various environmental stresses during their life cycle, among which drought stress is perhaps the most significant abiotic stress limiting plant growth and development. Arbuscular mycorrhizal (AM) fungi, a group of beneficial soil fungi, can enhance the adaptability and tolerance of their host plants to drought stress after infecting plant roots and establishing a symbiotic association with their host plant. Therefore, AM fungi represent an eco-friendly strategy in sustainable agricultural systems. There is still a need, however, to better understand the complex mechanisms underlying AM fungi-mediated enhancement of plant drought tolerance to ensure their effective use. AM fungi establish well-developed, extraradical hyphae on root surfaces, and function in water absorption and the uptake and transfer of nutrients into host cells. Thus, they participate in the physiology of host plants through the function of specific genes encoded in their genome. AM fungi also modulate morphological adaptations and various physiological processes in host plants, that help to mitigate drought-induced injury and enhance drought tolerance. Several AM-specific host genes have been identified and reported to be responsible for conferring enhanced drought tolerance. This review provides an overview of the effect of drought stress on the diversity and activity of AM fungi, the symbiotic relationship that exists between AM fungi and host plants under drought stress conditions, elucidates the morphological, physiological, and molecular mechanisms underlying AM fungi-mediated enhanced drought tolerance in plants, and provides an outlook for future research.

• Klíčová slova
• drought tolerance, mycorrhizae, plant physiology, symbiosis, water deficit,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Wheat is a staple food consumed by the majority of people in the world and its production needs to be doubled to feed the growing population. On the other hand, global wheat productivity is greatly affected due to drought and low fertility of soil under arid and semi-arid regions. Application of supplementary irrigation and plant growth-promoting rhizobacteria (PGPR) has been suggested as sustainable measures to combat drought stress and to improve soil fertility and, hence, crop yield. This research was undertaken to study the effect of supplementary irrigation together with a combination of various PGPR on the growth and yield of two wheat cultivars, namely Sardari and Sirvan. The results of variance analysis (mean of squares) showed that the effect of irrigation, cultivar, and irrigation and biofertilizer and irrigation on height, spike length, seed/spike, and numbers of spikes/m2, 1000-seed weight, and grain yield were significant at 1% probability level. The effect of cultivar and irrigation interactions showed that the highest grain yield was obtained in a treatment with two additional irrigations in Sirvan cultivar (5015.0 kg/ha) and Sardari (4838.9 kg/ha) as compared to the 3598 kg/ha and 3598.3 kg/h grain yield in Sirvan and Sardari cultivars with similar treatment, but without irrigation, i.e., dryland farming. Drought conditions significantly affected the wheat grain yield while supplementary irrigation resulted in 39.38% and 34.48% higher yields in Sirvan and Sardari cultivars.

• Klíčová slova
• biofertilizers, drought stress, irrigation, mycorrhiza, wheat,
• Publikační typ
• časopisecké články MeSH

Root-hair growth and development regulated by soil microbes is associated with auxin. In this background, we hypothesized that mycorrhizal fungal inoculation induces greater root-hair growth through stimulated auxin synthesis and transport under water stress conditions. Trifoliate orange (Poncirus trifoliata) was inoculated with an arbuscular mycorrhizal (AM) fungus (Funneliformis mosseae) under well-watered (WW) and drought stress (DS) for 9 weeks. Compared with non-AM seedlings, AM seedlings displayed significantly higher density, length, and diameter of root hairs and root indoleacetic acid (IAA) level, whereas lower total root IAA efflux, regardless of soil moisture status. Root PtYUC3 and PtYUC8 involved in IAA biosynthesis were up-regulated by mycorrhization under WW and DS, whereas AM-modulated expression in PtTAA1, PtTAR2, PtYUC4, and PtYUC6 depended on status of soil moisture. Mycorrhizal inoculation down-regulated the transcript level of root auxin efflux carriers like PtPIN1 and PtPIN3, whereas significantly up-regulated the expression of root auxin-species influx carriers like PtABCB19 and PtLAX2 under DS. These results indicated that AMF-stimulated greater root-hair growth of trifoliate orange under DS that is independent on AMF species is related with mycorrhiza-modulated auxin synthesis and transport, which benefits the host plant to enhance drought tolerance.

• MeSH
• biologický transport MeSH
• fyziologický stres * MeSH
• Glomeromycota růst a vývoj   fyziologie   MeSH
• kyseliny indoloctové metabolismus   MeSH
• messenger RNA genetika   metabolismus   MeSH
• mykorhiza růst a vývoj   fyziologie   MeSH
• období sucha * MeSH
• počet mikrobiálních kolonií MeSH
• Poncirus genetika   růst a vývoj   mikrobiologie   fyziologie   MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné geny MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• indoleacetic acid MeSH Prohlížeč
• kyseliny indoloctové MeSH
• messenger RNA MeSH
• rostlinné proteiny MeSH