Talk: Prof. Heribert Hirt
Desert plant microbes for enabling agriculture under extreme environmental conditions
Prof. Heribert Hirt
(DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), 23955-6900 Thuwal, Saudi Arabia)
Website : https://www.darwin21.org/
Here is our latest review on the mechanisms how microbes come in to make plants heat tolerant. Maybe interesting for the students to read before my lecture.
Beneficial microbes can enhance plant growth and provide abiotic and biotic stress tolerance to plants in extreme environments, but their underlying mechanisms are poorly understood. Enterobacter sp. SA187 is a root endophytic desert bacterium that maintains growth and yield of various monocot and dicot plants under various abiotic stress conditions. We compared the metabolic wirings of Arabidopsis and SA187 in the free-living and endophytic states. Upon plant interaction, massive changes in bacterial gene expression in chemotaxis, flagellar biosynthesis, quorum sensing and biofilm formation were observed. In both plant and bacteria, carbon, energy and sulfur metabolisms were modified. The importance of the S metabolism in plant salt stress was substantiated by observing that several sulfur metabolism mutants show hypersensitivity to salt stress which can be partially rescued by SA187. Moreover, salt stress-induced ROS accumulation in Arabidopsis was suppressed by SA187 in wild type and mutants of LSU2, a central chloroplast regulator linking sulfur metabolism to SOD activity. Sulfur levels in chloroplasts are monitored by the FRY1/SAL1 retrograde signaling pathway, mutants of which can also be partially rescued by SA187. We showed that SA187 provides a small sulfur metabolite to its host plant which regulates the ethylene signaling pathway. SA187 was also found to make plants resistant to heat stress in an ethylene-mediated manner. We further found that thermopriming and SA187 use the same heat stress response pathway regulating the key transcription factor HSFA2 to induce HSPs and anti-oxidative enzymes. Importantly, SA187 primes plants already in the absence of stress treatment, rendering plants more ready to react to abiotic stress challenges in a robust way. The potential of SA187 for agriculture was proven by enhancing stress tolerance and yield of various crops in the greenhouse and open field, showing that a single microbial strain can contribute to secure food production under environmental stress conditions.
- de Zelicourt A, Al-Yousif M, Hirt H.(2013) Rhizosphere microbes as essential partners for plant stress\ tolerance. Mol Plant 6:242-5.
- Andrés-Barrao C, Lafi FF, Alam I, de Zélicourt A, Eida AA, Bokhari A, Alzubaidy H, Bajic VB, Hirt H, Saad MM. (2017) Complete Genome Sequence Analysis of Enterobacter sp. SA187, a Plant Multi-Stress Tolerance Promoting Endophytic Bacterium.Front Microbiol. 8:2023
- de Zélicourt A, Synek L, Saad MM, Alzubaidy H, Jalal R, Xie Y, Andrés-Barrao C, Rolli E, Guerard F, Mariappan KG, Daur I, Colcombet J, Benhamed M, Depaepe T, Van Der Straeten D, Hirt H. (2018) Ethylene induced plant stress tolerance by Enterobacter sp. SA187 is mediated by 2-keto-4-methylthiobutyric acid production. PLoS Genet. 14(3):e1007273.
- Andrés-Barrao C, Alzubaidy H, Jalal R, Mariappan KG, de Zélicourt A, Bokhari A, Artyukh O, Alwutayd K, Rawat A, Shekhawat K, Almeida-Trapp M, Saad MM, Hirt H. (2021) Coordinated bacterial and plant sulfur metabolism in Enterobacter sp. SA187-induced plant salt stress tolerance. Proc Natl Acad Sci U S A. 2021 Nov 16;118(46):e2107417118.
- Shekhawat K, Saad MM, Sheikh A, Mariappan K, Al-Mahmoudi H, Abdulhakim F, Eida AA, Jalal R, Masmoudi K, Hirt H (2021) Root endophyte induced plant thermotolerance by constitutive chromatin modification at heat stress memory gene loci. EMBO Rep. 2021 Mar 3;22(3):e51049.
Hirt studied biochemistry at the Univ. of Cape Town and Vienna where he received his PhD in 1987. After post-doctoral fellowships at the Univ. of Oxford and Wageningen, he became a Professor of Genetics at the Univ. of Vienna. In 2007, he was nominated Director of the INRAe Plant Genomics Institute in Paris and of the Center for Desert Agriculture at KAUST in 2014. Hirt has a long-standing record on how plants can survive under abiotic or biotic stress conditions (h-index 91). His current research is focused on how plants can survive under abiotic or biotic stress conditions by identifying and using beneficial microbes of desert plants. His work aims to provide sustainable solutions to reestablish agriculture in arid regions by improving drought, heat and/or salt tolerance of a variety of crops.