Frontiers in Microbiology 01 frontiersin.org
Olive agroforestry shapes
rhizosphere microbiome
networks associated with annual
crops and impacts the biomass
production under low-rainfed
conditions
Ameni Ben zineb
1
, Karim Barkaoui
2,3
, Fatma Karray
4
, Najla
Mhiri
4
, Sami Sayadi
5
, Ahmed Mliki
1
and Mahmoud Gargouri
1
*
1
Laboratory of Plant Molecular Physiology, Centre of Biotechnology of Borj-Cedria, Hammam-Lif,
Tunisia,
2
CIRAD, UMR ABSys, Montpellier, France,
3
ABSys, Univ Montpellier, CIHEAM-IAMM, CIRAD,
INRAE, Institut Agro, Montpellier, France,
4
Laboratory of Environmental Bioprocesses, Centre of
Biotechnology of Sfax, Sfax, Tunisia,
5
Biotechnology Program, Center for Sustainable Development,
College of Arts and Sciences, Qatar University, Doha, Qatar
Agroforestry (AF) is a promising land-use system to mitigate water defciency,
particularly in semi-arid areas. However, the belowground microbes
associated with crops below trees remain seldom addressed. This study aimed
at elucidating the efects of olive AF system intercropped with durum wheat
(Dw), barely (Ba), chickpea (Cp), or faba bean (Fb) on crops biomass and their
soil-rhizosphere microbial networks as compared to conventional full sun
cropping (SC) under rainfed conditions. To test the hypothesis, we compared
the prokaryotic and the fungal communities inhabiting the rhizosphere of
two cereals and legumes grown either in AF or SC. We determined the most
suitable annual crop species in AF under low-rainfed conditions. Moreover,
to deepen our understanding of the rhizosphere network dynamics of annual
crops under AF and SC systems, we characterized the microbial hubs that are
most likely responsible for modifying the microbial community structure and
the variability of crop biomass of each species. Herein, we found that cereals
produced signifcantly more above-ground biomass than legumes following
in descending order: Ba > Dw > Cp > Fb, suggesting that crop species play a
signifcant role in improving soil water use and that cereals are well-suited to
rainfed conditions within both types of agrosystems. The type of agrosystem
shapes crop microbiomes with the only marginal infuence of host selection.
However, more relevant was to unveil those crops recruits specifc bacterial
and fungal taxa from the olive-belowground communities. Of the selected soil
physicochemical properties, organic matter was the principal driver in shaping
the soil microbial structure in the AF system. The co-occurrence network
analyses indicated that the AF system generates higher ecological stability
than the SC system under stressful climate conditions. Furthermore, legumes’
rhizosphere microbiome possessed a higher resilient capacity than cereals.
We also identifed diferent fungal keystones involved in litter decomposition
and drought tolerance within AF systems facing the water-scarce condition and
TYPE Original Research
PUBLISHED 28 October 2022
DOI 10.3389/fmicb.2022.977797
OPEN ACCESS
EDITED BY
Blanca B. Landa,
Institute for Sustainable Agriculture (CSIC),
Spain
REVIEWED BY
Carmen Gómez-Lama Cabanás,
Institute for Sustainable Agriculture (CSIC),
Spain
Elizabeth Temitope Alori,
Landmark University,
Nigeria
Alexandre Barretto De Menezes,
National University of Ireland, Ireland
*CORRESPONDENCE
Mahmoud Gargouri
mahmoud.gargouri@cbbc.rnrt.tn
SPECIALTY SECTION
This article was submitted to
Microbe and Virus Interactions with Plants,
a section of the journal
Frontiers in Microbiology
RECEIVED 24 June 2022
ACCEPTED 06 October 2022
PUBLISHED 28 October 2022
CITATION
Ben zineb A, Barkaoui K, Karray F, Mhiri N,
Sayadi S, Mliki A and Gargouri M (2022)
Olive agroforestry shapes rhizosphere
microbiome networks associated with
annual crops and impacts the biomass
production under low-rainfed conditions.
Front. Microbiol. 13:977797.
doi: 10.3389/fmicb.2022.977797
COPYRIGHT
© 2022 Ben zineb, Barkaoui, Karray, Mhiri,
Sayadi, Mliki and Gargouri. This is an open-
access article distributed under the terms
of the Creative Commons Attribution
License (CC BY). The use, distribution or
reproduction in other forums is permitted,
provided the original author(s) and the
copyright owner(s) are credited and that
the original publication in this journal is
cited, in accordance with accepted
academic practice. No use, distribution or
reproduction is permitted which does not
comply with these terms.