Identifying potential molecular factors involved in Bacillus
amyloliquefaciens 5113 mediated abiotic stress tolerance in
I. A. Abd El-Daim
, S. Bejai
, I. Fridborg
& J. Meijer
1 Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala, Sweden
2 Department of Microbiology, Soils, Water and Environment Research Institute, Agricultural Research Centre, Giza, Egypt
Abiotic stress; Bacillus; cDNA-AFLP; VIGS;
Islam A. Abd El-Daim, Department of
Microbiology, Soils, Water and Environment
Research Institute, Agricultural Research
Centre, Giza, Egypt.
Received: 9 July 2017; Accepted: 9 December
Abiotic stressors are main limiting factors for agricultural production around the
world. Plant growth-promoting bacteria have been successfully used to improve abi-
otic stress tolerance in several crops including wheat. However, the molecular changes
involved in the improvement of stress management are poorly understood.
The present investigation addressed some molecular factors involved in bacterially
induced plant abiotic stress responses by identifying differentially expressed genes in
wheat (Triticum aestivum) seedlings treated with the beneﬁcial bacterium Bacillus
amyloliquefaciens subsp. plantarum UCMB5113 prior to challenge with abiotic stress
conditions such as heat, cold or drought.
cDNA-AFLP analysis revealed differential expression of more than 200 transcript-
derived fragments (TDFs) in wheat leaves. Expression of selected TDFs was conﬁrmed
using RT-PCR. DNA sequencing of 31 differentially expressed TDFs revealed signiﬁ-
cant homology with both known and unknown genes in database searches. Virus-
induced gene silencing of two abscisic acid-related TDFs showed different effects upon
heat and drought stress.
We conclude that treatment with B. amyloliquefaciens 5113 caused molecular modiﬁ-
cations in wheat in order to induce tolerance against heat, cold and drought stress.
Bacillus treatment provides systemic effects that involve metabolic and regulatory
functions supporting both growth and stress management.
Plant growth is continuously affected by various environmental
factors, where abiotic stressors such as drought, salinity and
temperature extremes are the most limiting factors for crop
production on a global basis (Krasensky & Jonak 2012).
Throughout evolution plants have managed such stresses
through adaptations that often require several modiﬁcations,
enabling survival in harsh environments (Nakashima et al.
2009). Plant breeding aiming for increased yield frequently
overlooks and may even compromise stress tolerance traits.
Several economically important plants are known for their sen-
sitivity to abiotic stress, which often results in substantial losses
for crop production under unfavourable conditions (Bita &
Gerats 2013). Moreover, with climate change, plants will have
to managed more unfavourable growth conditions that could
seriously jeopardise future food security (Pradhan et al. 2014).
Plants respond to stress through various sensing systems, and
the transduced signals change expression of numerous genes
associated with stress tolerance (Nakashima et al. 2009). Stress-
inducible genes confer protection against environmental stress
directly, through various factors such as chaperones, anti-freez-
ing proteins, antioxidants and osmotic regulators, or indirectly,
through factors regulating gene expression and signalling
(Yoshida et al. 2014).
Increasing crop plant productivity and enhancing resistance
or tolerance against various stress factors have become major
aims for agriculture (Wahid et al. 2007). Generally, such goals
can be achieved through genetic improvement by breeding
programmes or the use of genetic engineering technology
(Warren 1998). Although a genetic approach may generate tol-
erant plants, it is time consuming, costly and assumes the avail-
ability of the desired traits in the germplasm when it comes to
breeding, while transgenic technologies are not universally
accepted (Wahid et al. 2007). Another, as yet mostly unex-
plored, tool to improve stress tolerance is the use of epigenetic
diversity to assist breeding (Gallusci et al. 2017). Other meth-
ods to improve stress tolerance in plants include treatment of
plants or seeds with natural and synthetic compounds or bio-
logical agents like bacteria and fungi. This stimulation process
of the latent resources of plant defence is referred to as priming
(Conrath et al. 2006). Plant growth-promoting bacteria
(PGPB) refer to a group of bacteria that enhance plant growth
and productivity through several mechanisms (Bashan et al.
2006). Several PGPB strains are also known to stimulate abiotic
stress tolerance in plants by priming of induced systemic
Plant Biology 20 (2018) 271–279 © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands
Plant Biology ISSN 1435-8603