scholarly journals Direct conversion of carlactonoic acid to orobanchol by cytochrome P450 CYP722C in strigolactone biosynthesis

2019 ◽  
Vol 5 (12) ◽  
pp. eaax9067 ◽  
Author(s):  
Takatoshi Wakabayashi ◽  
Misaki Hamana ◽  
Ayami Mori ◽  
Ryota Akiyama ◽  
Kotomi Ueno ◽  
...  

Strigolactones (SLs) are carotenoid-derived phytohormones and rhizosphere signaling molecules for arbuscular mycorrhizal fungi and root parasitic weeds. Why and how plants produce diverse SLs are unknown. Here, cytochrome P450 CYP722C is identified as a key enzyme that catalyzes the reaction of BC-ring closure leading to orobanchol, the most prevalent canonical SL. The direct conversion of carlactonoic acid to orobanchol without passing through 4-deoxyorobanchol is catalyzed by the recombinant enzyme. By knocking out the gene in tomato plants, orobanchol was undetectable in the root exudates, whereas the architecture of the knockout and wild-type plants was comparable. These findings add to our understanding of the function of the diverse SLs in plants and suggest the potential of these compounds to generate crops with greater resistance to infection by noxious root parasitic weeds.

Agronomy ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 131 ◽  
Author(s):  
Ludovico Formenti ◽  
Sergio Rasmann

Arbuscular mycorrhizal (AM) fungi favor plant growth by improving nutrient acquisition, but also by increasing their resistance against abiotic and biotic stressors, including herbivory. Mechanisms of AM fungal mediated increased resistance include a direct effect of AM fungi on plant vigor, but also a manipulation of the hormonal cascades, such as the systemic activation of jasmonic acid (JA) dependent defenses. However, how AM fungal inoculation and variation in the endogenous JA production interact to produce increased resistance against insect herbivores remains to be further elucidated. To address this question, three genotypes of Solanum lycopersicum L., a JA-biosynthesis deficient mutant, a JA over-accumulating mutant, and their wild-type were either inoculated with AM fungi or left un-inoculated. Plant growth-related traits and resistance against Spodoptera littoralis (Boisduval) caterpillars, a major crop pest, were measured. Overall, we found that deficiency in JA production reduced plant development and were the least resistant against S. littoralis. Moreover, AM fungi increased plant resistance against S. littoralis, but such beneficial effect was more pronounced in JA-deficient plant than on JA over-accumulating plants. These results highlight that AM fungi-driven increased plant resistance is negatively affected by the ability of plants to produce JA and that AM fungi complement JA-mediated endogenous plant defenses in this system.


2019 ◽  
Author(s):  
Kena Casarrubias-Castillo ◽  
Josaphat M Montero-Vargas ◽  
Nicole Dabdoub-González ◽  
Robert Winkler ◽  
Norma A Martinez-Gallardo ◽  
...  

A previous study with spr2 mutant tomato plants which are negatively affected in the synthesis of jasmonic acid (JA), suggested that JA regulates the arbuscular mycorrhizal fungi (AMF) colonization via the control of carbon (C) partitioning. Although this and other studies have suggested the important positive role played by JA in the regulation of AMF root colonization in tomato plants, it is currently unclear how different host plant genetic backgrounds affect gene expression and secondary metabolites variation during JA-dependent mycorrhization. In this study, wild type and spr2 mutant tomato plants having “low”, “medium” and “high” mycorrhizal colonization with Rhizophagus irregularis, were analyzed independently using transcriptomic and untargeted metabolomic approaches. The results obtained revealed that the degree of mycorrhizal colonization efficiency could be associated with contrasting expression levels of certain key genes controlling gibberellin signaling, ethylene biosynthesis and signaling, and synthesis of apocarotenoids, phenylpropanoids and tomatine, in roots. Only a few wound responsive genes, including JA signaling and biosynthesis genes, such as Prosystemin and JAZ2 were found to influence AMF colonization. Conversely, a systemic and JA-dependent induction/ repression of genes different from those altered in roots was detected in leaves of mycorrhizal plants. The most significant changes in metabolite abundance were detected in roots with reduced AMF colonization. Included among the latter were metabolites known to be associated with important aspects of AMF symbiosis, such as signaling, nutrient exchange and modulation of pathogen defense response. Αlpha-tomatine levels appeared to be an important factor, whose abundance negatively correlated wit h AMF colonization levels in tomato, suggesting a regulatory role for JA in the synthesis of this metabolite during the AMF symbiosis.


2019 ◽  
Author(s):  
Kena Casarrubias-Castillo ◽  
Josaphat M Montero-Vargas ◽  
Nicole Dabdoub-González ◽  
Robert Winkler ◽  
Norma A Martinez-Gallardo ◽  
...  

A previous study with spr2 mutant tomato plants which are negatively affected in the synthesis of jasmonic acid (JA), suggested that JA regulates the arbuscular mycorrhizal fungi (AMF) colonization via the control of carbon (C) partitioning. Although this and other studies have suggested the important positive role played by JA in the regulation of AMF root colonization in tomato plants, it is currently unclear how different host plant genetic backgrounds affect gene expression and secondary metabolites variation during JA-dependent mycorrhization. In this study, wild type and spr2 mutant tomato plants having “low”, “medium” and “high” mycorrhizal colonization with Rhizophagus irregularis, were analyzed independently using transcriptomic and untargeted metabolomic approaches. The results obtained revealed that the degree of mycorrhizal colonization efficiency could be associated with contrasting expression levels of certain key genes controlling gibberellin signaling, ethylene biosynthesis and signaling, and synthesis of apocarotenoids, phenylpropanoids and tomatine, in roots. Only a few wound responsive genes, including JA signaling and biosynthesis genes, such as Prosystemin and JAZ2 were found to influence AMF colonization. Conversely, a systemic and JA-dependent induction/ repression of genes different from those altered in roots was detected in leaves of mycorrhizal plants. The most significant changes in metabolite abundance were detected in roots with reduced AMF colonization. Included among the latter were metabolites known to be associated with important aspects of AMF symbiosis, such as signaling, nutrient exchange and modulation of pathogen defense response. Αlpha-tomatine levels appeared to be an important factor, whose abundance negatively correlated wit h AMF colonization levels in tomato, suggesting a regulatory role for JA in the synthesis of this metabolite during the AMF symbiosis.


2021 ◽  
Vol 22 (8) ◽  
Author(s):  
Asri Subkhan Mahulette ◽  
Anggra Alfian ◽  
ABDUL KARIM KILKODA ◽  
IMELDA JEANETTE LAWALATA ◽  
DESSY ARIYANI MARASABESSY ◽  
...  

Abstract. Mahulette AS, Alfian A, Kilkoda KA, Lawalata IJ, Marasabessy DA, Tanasale VL, Makaruku MH. 2021. Isolation and identification of indigenous Arbuscular Mycorrhizal Fungi (AMF) of forest clove rhizosphere from Maluku, Indonesia. Biodiversitas 22: 3613-3619. Forest clove is classified as wild-type and endemic to the Maluku (Moluccas) Islands, Indonesia. The different condition of growing areas causes various types of Arbuscular Mycorrhizal Fungi (AMF) associated with forest clove. The study aimed to identify and obtain indigenous AMF inoculums from the forest clove rhizosphere from two distribution areas in Maluku. The results of AMF identification found two types of spores from the genus Glomus in the rhizosphere of forest cloves from Ambon Island with a spore density of 35/50 g of soil. In comparison, three spores were found in Seram Island, two from the genus Scutellospora and one from the Acaulospora. With an overall spore density of 5/50 g of soil. After culture trapping, there was a change in type and an increase in spore density in soil samples from the rhizosphere of the two forest clove distribution areas. Soil samples from Ambon after trapping culture obtained two new types of spores from the genus Acaulospora with a total spore number of 57/50 g soil while in soil samples from Seram found three new types of spores from the genus Glomus with a total spore count of 104/50 g of soil.


2007 ◽  
Vol 53 (6) ◽  
pp. 702-709 ◽  
Author(s):  
Jose M. Scervino ◽  
María A. Ponce ◽  
Rosa Erra-Bassells ◽  
Josefina Bompadre ◽  
Horst Vierheilig ◽  
...  

No clear data are available on how flavonoids from different chemical groups affect root colonization by arbuscular mycorrhizal fungi (AMF) and whether flavonoids affecting the presymbiotic growth of AMF also affect root colonization by AMF. In the present work, we compared the effect of flavones (chrysin and luteolin) and flavonols (kaempferol, morin, isorhamnetin, and rutin) on root colonization (number of entry points and degree of root colonization) of tomato plants ( Lycopersicum esculentum L.) with the effect of these flavonoids on the presymbiotic growth of these AMF, which has been reported in a recent study. With all tested AMF ( Gigaspora rosea , Gigaspora margarita , Glomus mosseae, and Glomus intraradices) a correlation between the number of entry points and the percentage of root colonization was found. When the number of entry points was high, root colonization was also enhanced. Application of the flavones chrysin and luteolin and of the flavonol morin increased the number of entry points and the degree of colonization,whereas the flavonols kaempferol, isorhamnetin, and rutin showed no effect. These results show that in contrast to their effect on the presymbiotic growth of the AMF on the level of root colonization, the tested flavonoids do not exhibit a genus- and species-specificity. Moreover, comparison of our data with the data obtained by J.M. Scervino, M.A. Ponce, R. Erra-Bassells, H. Vierheilig, J.A. Ocampo, and A. Godeas. (2005a. J. Plant Interact. 15: 22–30) indicates that a positive effect on the hyphal growth of AMF does not necessarily result in an enhanced AM root colonization, further indicating that the mode of action of flavonoids at the level of root colonization is more complex.


Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 438 ◽  
Author(s):  
María José Gómez-Bellot ◽  
Beatriz Lorente ◽  
María Jesús Sánchez-Blanco ◽  
María Fernanda Ortuño ◽  
Pedro Antonio Nortes ◽  
...  

The use of reclaimed water (RW) is considered as a means of maintaining agricultural productivity under drought conditions. However, RW may contain high concentrations of salts. The use of some practices, such as biofertilizers and organic substrates, is also becoming increasingly important in agricultural. production. The aim of this study was to evaluate the application of a mixed substrate (with coconut fibre) and arbuscular mycorrhizal fungi (AMF) on water relations, nutrient uptake and productivity in tomato plants irrigated with saline RW in a commercial greenhouse. Saline RW on its own caused a nutrient imbalance and negatively affected several physiological parameters. However, the high water-holding capacity of coconut fibre in the mixed substrate increased water and nutrient availability for the plants. As a consequence, leaf water potential, gas exchange, some fluorescence parameters (PhiPSII, Fv’/Fm’, qP and ETR) and fruit size and weight improved, even in control irrigation conditions. The use of AMF improved only some parameters because of the low percentage of colonization, suggesting that AMF effectiveness in commercial field conditions is slower and dependent of several factors.


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