Transcriptome changes induced by arbuscular mycorrhizal fungi in sunflower (Helianthus annuus L.) roots

Abstract

Arbuscular mycorrhizal (AM) fungi are essential elements of soil fertility, plant nutrition and productivity, facilitating soil mineral nutrient uptake. Helianthus annuus is a non-model, widely cultivated species. Here we used an RNA-seq approach for evaluating gene expression variation at early and late stages of mycorrhizal establishment in sunflower roots colonized by the arbuscular fungus Rhizoglomus irregulare. mRNA was isolated from roots of plantlets at 4 and 16 days after inoculation with the fungus. cDNA libraries were built and sequenced with Illumina technology. Differential expression analysis was performed between control and inoculated plants. Overall 726 differentially expressed genes (DEGs) between inoculated and control plants were retrieved. The number of up-regulated DEGs greatly exceeded the number of down-regulated DEGs and this difference increased in later stages of colonization. Several DEGs were specifically involved in known mycorrhizal processes, such as membrane transport, cell wall shaping, and other. We also found previously unidentified mycorrhizal-induced transcripts. The most important DEGs were carefully described in order to hypothesize their roles in AM symbiosis. Our data add a valuable contribution for deciphering biological processes related to beneficial fungi and plant symbiosis, adding an Asteraceae, non-model species for future comparative functional genomics studies.

Flowering plant immune repertoires expand under mycorrhizal symbiosis

“…(). Similarly, transcriptomic studies of genes up‐regulated in response to AM colonization find some MycEx genes, but no family is over‐represented (Sugimura & Saito, ; Recchia et al., ; Vangelisti et al., ; and Supporting Information Table ). Transcriptomic studies do report up‐regulation of defense‐related genes following AM colonization, but these genes are mostly downstream of the signaling pathways represented by the MycEx familes (Calabrese et al., ; Hohnjec, Vieweg, Puhler, Becker, & Kuster, ).…”

“…Vangelisti et al. () used RNA‐seq to determine the transcriptomes of Helianthus annuus seedling roots 16 days after inoculation with the AM fungal species Rhizoglomus irregulare . Compared to controls without the inoculation, they found 694 genes up‐regulated in AM plants.…”

“…A search among gene lists related to arbuscular mycorrhization finds some MycEx genes, but they are not over-represented in any set we examined (Bravo et al, 2016;Delaux et al, 2014;Recchia et al, 2018;Sugimura & Saito, 2017;Vangelisti et al, 2018) (Supporting Information Table S8).…”

Transcriptome Analysis of Wheat Roots Reveals a Differential Regulation of Stress Responses Related to Arbuscular Mycorrhizal Fungi and Soil Disturbance

“…Mycorrhizal colonization induces important morphological and functional changes in plant roots, and next generation sequencing techniques can be conveniently used for the analysis of transcriptome profiling during plant/fungi interactions. In recent years, several studies have focused on the effect of mycorrhizal colonization on plant molecular responses (e.g., [31,33,[52][53][54]), mostly by inoculating plants with a single AMF species and observing the transcriptomic changes with and without symbiosis. Here, we report the findings from a different approach: with the a priori knowledge that different preceding plant species induce different mycorrhizal communities on wheat roots [27], and that different AMF established symbiotic communities provide a differential protection against soil manganese toxicity [7,27], we concomitantly looked into wheat and AMF-derived transcripts to gain a comprehensive view of the regulation of gene expression related to plant tolerance against excess Mn.…”

“…There are some studies where plant transcriptional responses to different single AMF species or AMF consortia were compared [28][29][30], but most of the studies have only evaluated plant transcriptional responses by inoculating with one AMF isolate and comparing the plant response without the fungus (see for example reference [31]). In natural conditions, the plants interact with a multitude of AMF species.…”