Different patterns in root and soil fungal diversity drive plant productivity of the desert truffle <i>Terfezia claveryi</i> in plantation

SummaryThe desert truffle Terfezia claveryi is one of the few mycorrhizal fungi currently in cultivation in semiarid and arid areas. Agroclimatic parameters seem to affect its annual yield, but there is no information on the influence of biotic factors. In this study, fungal diversity was analysed by high‐throughput sequencing of the ITS2 rDNA region from soil and root samples to compare productive and non‐productive mycorrhizal plants in a 4‐years old plantation (Murcia, Spain). The fungal metaprofile was dominated by Ascomycota phylum. Desert truffle productivity was driven by different patterns of fungal species composition in soil (species replacement) and root (species richness differences). Moreover, positive associations for ectomycorrhizal and negative for arbuscular mycorrhizal guilds were found in productive roots, and positive associations for fungal parasite‐plant pathogen guild in non‐productive ones. Soil samples were dominated by pathotroph and saprotroph trophic modes, showing positive associations for Aureobasidium pullulans and Alternaria sp. in productive areas, and positive associations for Fusarium sp. and Mortierella sp. were found in non‐productive soils. Finally, some significant OTUs were identified and associated to ascocarp producing patches, which could serve as predictive and location markers of desert truffle production

Caracterización de la actividad fosfatasa y estudio de la respuesta a la sequía en la simbiosis micorrícica de Helianthemum Almeriense Pau y Terfezia Claveryi Chatin / directoras, María Asunción Morte Gómez, Manuela Pérez Gilabert.

Tesis-Universidad de Murcia.Consulte la tesis en: BCA. GENERAL. ARCHIVO UNIVERSITARIO. TM 4263

Identification of an Alternative rRNA Post-transcriptional Maturation of 26S rRNA in the Kingdom Fungi

Despite of the integrity of their RNA, some desert truffles present a non-canonical profile of rRNA where 3.3 kb is absent, 1.8 kb is clear and a band of 1.6 kb is observed. A similar rRNA profile was identified in organisms belonging to different life kingdoms, with the exception of the Kingdom Fungi, as a result of a split LSU rRNA called hidden gap. rRNA profiles of desert truffles were analyzed to verify the presence of the non-canonical profile. The RNA of desert truffles and yeast were blotted and hybridized with probes complementary to LSU extremes. RACE of LSU rRNA was carried out to determine the LSU rRNA breakage point. LSU rRNA of desert truffles presents a post-transcriptional cleavage of five nucleotides that generates a hidden gap located in domain D7. LSU splits into two molecules of 1.6 and 1.8 kb. Similar to other organisms, a UAAU tract, downstream of the breakage point, was identified. Phylogenetic comparison suggests that during fungi evolution mutations were introduced in the hypervariable D7 domain, resulting in a sequence that is specifically post-transcriptionally cleaved in some desert truffles

Design and Validation of qPCR-Specific Primers for Quantification of the Marketed <i>Terfezia claveryi</i> and <i>Terfezia crassiverrucosa</i> in Soil

Desert truffle crop is a pioneer in southeastern Spain, a region where native edible hypogeous fungi are adapted to the semiarid areas with low annual rainfall. Terfezia claveryi Chatin was the first species of desert truffle to be cultivated, and has been increasing in recent years as an alternative rainfed crop in the Iberian Peninsula. However, its behaviour in the field has yet not been investigated. For this purpose, specific primers were designed for the soil DNA quantification of both T. claveryi and Terfezia crassiverrucosa and a real-time qPCR protocol was developed, using the ITS rDNA region as a target. Moreover, a young desert truffle orchard was sampled for environmental validation. The results showed the highest efficiency for the TerclaF3/TerclaR1 primers pair, 89%, and the minimal fungal biomass that could be reliable detected was set at 4.23 µg mycelium/g soil. The spatial distribution of fungal biomass was heterogeneous, and there was not a direct relationship between the quantity of winter soil mycelium and the location/productivity of desert truffles. This protocol could be applied to tracking these species in soil and understand their mycelial dynamics in plantations and wild areas

Spring stomatal response to vapor pressure deficit as a marker for desert truffle fruiting

©. This manuscript version is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by /4.0/ This document is the Accepted version of a Published Work that appeared in final form in [Mycorrhiza]. To access the final edited and published work see[https://doi.org/10.1007/s00572-020-00966-8]The cultivation of desert truffle Terfezia claveryi using Helianthemum almeriense as a host plant has recently become a solid alternative crop in the Mediterranean region due to its adaptation to arid and semiarid ecosystems, which are expected to increase during the following years because of climate change. However, management models are still being developed in order to improve and stabilize the production, which varies greatly from one year to another. According to gatherers and farmers, one of the key factors for desert truffle production is the plant phenology in spring, which, in turn, depends on environmental conditions. In this manuscript, we have characterized the physiological, morphological, and molecular responses of the mycorrhizal plants in spring, coinciding with the fructification period of the plant and fungal species. Thanks to this characterization, a sigmoidal relationship between stomatal conductance and vapor pressure deficit (VPD)was found,which can be used as amarker of plant phenological switch. In order to confirmthat this phenology status is related to desert truffle fructification, this marker has been successfully correlated to total truffle production. The results of this manuscript suppose a big step forward that will help to develop management models for the desert truffle crop

Cultivation of Desert Truffles—A Crop Suitable for Arid and Semi-Arid Zones

Desert truffles are edible hypogeous (forming fruit bodies below ground) fungi that grow in semi-arid and arid areas. They are highly valued for both their culinary and medicinal properties in the Mediterranean basin, the Middle East and the Gulf areas. Desert truffles form mycorrhizae mostly with plants belonging to the Cistaceae family, mainly with Helianthemum species. These truffles are still, usually, collected from the wild, but loss of habitats due to urbanization, desertification, intensive agriculture and global warming, along with an urgent need to develop new crops adapted to arid conditions, are currently hastening efforts towards their domestication. Here, we sum up the successful research leading to cultivation of this crop, based on plots that were established in sandy to silt soils with high pH values and low mineral contents. We report suitable methods for production of mycorrhized seedlings and preferred planting methods. We found that under natural conditions yields are affected by water availability, so irrigation regimes to ensure good yields were sought. Although good yields were indeed obtained in some years, fluctuations in yields over the years were significant; the reasons for this are not entirely clear and are currently under study. This crop is particularly well suited to relatively marginal conditions but prospects for establishment of desert truffles as a niche crop for arid and semi-arid areas depend on further improvements in yields

The crop of desert truffle depends on agroclimatic parameters during two key annual periods

Desert truffles have become an alternative agricultural crop in semiarid areas of the Iberian Peninsula due to their much appreciated edible value and their low water requirements for cultivation. Although most studies related to desert truffle production point to the sole importance of precipitation, this work is the first systematic study carried out to characterize whether other important agroclimatic parameters, for example reference evapotranspiration, soil water potential, relative air humidity %, aridity index or air vapour pressure deficit, may have an impact on a desert truffle production in an orchard with mycorrhizal plants of Helianthemum almeriense × Terfezia claveryi for 15 years from the plantation. The results show for the first time that T. claveryi production has two key periods, during its annual cycle: autumn (September to October) and spring (end of March). The aridity index and soil water potential seem to be the most manageable parameters in the field and can be easily controlled by applying irrigation during the abovementioned periods. Agroclimatic parameters can influence the final crop a long time before the desert truffle fruiting season contrary to what happens with other edible mycorrhizal mushrooms. Four different models to manage desert truffle plantations are proposed based on these agroclimatic parameters in order to optimize and stabilize carpophore fructifications over the years

Image_1_Identification of an Alternative rRNA Post-transcriptional Maturation of 26S rRNA in the Kingdom Fungi.pdf

<p>Despite of the integrity of their RNA, some desert truffles present a non-canonical profile of rRNA where 3.3 kb is absent, 1.8 kb is clear and a band of 1.6 kb is observed. A similar rRNA profile was identified in organisms belonging to different life kingdoms, with the exception of the Kingdom Fungi, as a result of a split LSU rRNA called hidden gap. rRNA profiles of desert truffles were analyzed to verify the presence of the non-canonical profile. The RNA of desert truffles and yeast were blotted and hybridized with probes complementary to LSU extremes. RACE of LSU rRNA was carried out to determine the LSU rRNA breakage point. LSU rRNA of desert truffles presents a post-transcriptional cleavage of five nucleotides that generates a hidden gap located in domain D7. LSU splits into two molecules of 1.6 and 1.8 kb. Similar to other organisms, a UAAU tract, downstream of the breakage point, was identified. Phylogenetic comparison suggests that during fungi evolution mutations were introduced in the hypervariable D7 domain, resulting in a sequence that is specifically post-transcriptionally cleaved in some desert truffles.</p

Laccaria bicolor aquaporin LbAQP1 is required for Hartig net development in trembling aspen ( Populus tremuloides )

The development of ectomycorrhizal associations is crucial for growth of many forest trees. However, the signals that are exchanged between the fungus and the host plant during the colonization process are still poorly understood. In this study, we have identified the relationship between expression patterns of Laccaria bicolor aquaporin LbAQP1 and the development of ectomycorrhizal structures in trembling aspen (Populus tremuloides) seedlings. The peak expression of LbAQP1 was 700‐fold higher in the hyphae within the root than in the free‐living mycelium after 24 h of direct interaction with the roots. Moreover, in LbAQP1 knock‐down strains, a non‐mycorrhizal phenotype was developed without the Hartig net and the expression of the mycorrhizal effector protein MiSSP7 quickly declined after an initial peak on day 5 of interaction of the fungal hyphae with the roots. The increase in the expression of LbAQP1 required a direct contact of the fungus with the root and it modulated the expression of MiSSP7. We have also determined that LbAQP1 facilitated NO, H2O2 and CO2 transport when heterologously expressed in yeast. The report demonstrates that the L. bicolor aquaporin LbAQP1 acts as a molecular signalling channel, which is fundamental for the development of Hartig net in root tips of P. tremuloides.Fil: Navarro Ródenas, Alfonso. University of Alberta; CanadáFil: Xu, Hao. University of Alberta; CanadáFil: Kemppainen, Minna Johanna. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Micología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pardo, Alejandro Guillermo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Micología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zwiazek, Janusz J.. University of Alberta; Canad