Joseph Gottlieb Kölreuter Institut für Pflanzenwissenschaften (JKIP)
Karlsruhe Institute for Technology (KIT)
Scientific portrait
Our research
Life is not easy. There are two ways to respond to this – run away or adapt. Plants cannot run, so they need to adapt to adverse environments. At the Department of Molecular Cell Biology we try to understand, how. The key are plant cells, there versatility and their resilience. How do they adjust their shape and metabolism to challenges from the environment? How do they sense, process, and adapt to different stresses and their combinations? How can evolution as most successful problem-solving strategy on our planet help to find genes of resilience in the biodiversity we have at hand?
As scientists we want to understand. However, we also want to use this knowledge to change something in the world. Therefore, we are working with crop plants, such as rice, sorghum, and grapevine. In the past, we have dissected the signalling regulating the immune system of grapevine and found that jasmonates, central regulators of plant stress, are crucial for decision making – whether a cell under stress will deploy adaptive responses, or whether it will decide to sacrifice its life for the sake of the entire organism depends on the temporal signature of jasmonate signalling.
Our contribution to Kliwiresse
A stress-induced change, while being interesting, still does not tell much – it could report adaptation, but it could as well be a simple consequence of stress, a marker for damage. The extensive and complex data sets that will arise from this project need to be interpreted. We bring in more than two decades of expertise in the field of plant stress with a strong focus on the molecular aspects of signalling. This will help to decide, what the observed differences actually mean.
Our second contribution to the project is our collection of the European Wild Grapevine (Vitis sylvestris). This wild ancestor of our grapevine has become almost extinct. Originally in the context of a protection project, we were able to establish a collection representing the entire gene pool for this wild species still available in Germany and beyond.
For this collection, the genomes have been deciphered and organised in the GrapeKIT database, which for any gene of interest allows to search, what variants Nature has created and then get the respective plant. As we know from an extensive comparison between numerous genomes (Dong et al., 2023), grapevine, during its late evolution and during its interaction with humans, had to cope with quite different environmental challenges and impressive dynamics of genetic exchange and migration. The legacy of this history can now be mined for factors promoting climate resilience. For first candidates, crossing populations have already been established with partner JKI.
What did we achieve
How did we proceed?
The question, how grapevine is sensing and processing heat stress, has remained without answer. Therefore, we confronted young plants of Riesling (heat-susceptible) and the wild grapevine Hördt 29 (heat-tolerant) with heat stress under controlled conditions and monitored molecular and physiological responses that are linked with tolerance. First, we had to solve a couple of technical and methodological questions to simulate the situation in the vineyard close to reality. What duration of stress should we apply? What temperature should be administered? Which type of measurements are informative? Can we find methods to investigate the situation in real vineyards, where conditions cannot be controlled, but just monitored in retrospect?
Our toolbox
Meanwhile, we have developed an efficient toolbox to measure heat tolerance of different grapevines. This toolbox contains non-invasive physiological methods such as quanitification of stomatal opening or photosynthetic parameters, molecular determination of stress levels such as measuring reactive oxygen species, the activity of stress-signal and defence genes, but also methods to determine the stress memory of a plant, such as carbon-isotope discrimination or determination of jasmonate degradation products. Since experiments with plants are very laborious and require a lot of time, space, work, and infrastructure, we searched for ways to assay, rapidly and reliably, heat tolerance of plants using leaf discs.
Such a test could be established successfully, which allowed to measure heat tolerance of several varieties. We found that Riesling and Morio Muscat are very heat sensitive, while the wild grapevine Hördt 29, but also Chardonnay performed very well, and the PiWi-variety Calardis Blanc was intermediate. Next summer, this method will help to screen a large number of varieties, but also wild grapevines.
How can grapevine develop heat tolerance?
As central factors for a superior heat tolerance, we could identify a rapid activation of heat-shock proteins, but also a better communication between mitochondria and the nucleus. At the start of a heat episope, all plants, no matter, whether they are susceptible or tolerant, open their stomata to lower leaf temperature by transpiration of water (similar to us humans, when we sweat to lower the body temperature). However, while susceptible plants, such as our Riesling, need to keep their stomata open even after days and, thus, loose a lot of water, the tolerant wild graprevine Hördt 29 can already close stomata again after a few hours and, thus, can safeguard its water resources much better.
Recent publications relevant to the project
Gong PJ, Metzger C, Khattab I, Kaźmierczak A, Riemann M, Nick P (2023) Two ways to die: species dependent PCD modes in grapevine cells. Plant Science 332, 111695
Dong Y, Duan S, Xia Q, Liang Zh, Dong X, Margaryan K, Musayev M, Goryslavets S, Zdunić G, Bert PF, Lacombe T, Maul E, Nick P, et al. (2023) Dual domestications and origin of traits in grapevine evolution. Science, 379, 892-901
Sofi KG, Metzger C, Riemann M, Nick P (2023) Chitosan triggers actin remodelling and activation of defence genes that is repressed by calcium influx in grapevine cells. Plant Science 326, 111527
Daldoul S, Hanzouli F, Hamdi Z, Chenenaoui S, Wetzel T, Nick P, Mliki A, Gargouri M (2022) The root transcriptome dynamics reveals new valuable insights in the salt-resilience mechanism of Mediterranean wild grapevine (Vitis vinifera subsp. sylvestris). Front Plant Sci 13, 1077710
Khattab IM, Sahi VP, Baltenweck R, Grondard AM, Hugueney P, Bieler E, Dürrenberger M, Riemann M, Nick P (2021) Ancestral chemotypes of cultivated grapevine with resistance to Botryosphaeriaceae related Dieback allocate metabolism towards bioactive stilbenes. New Phytologist 229, 1133-1146
Ge XS, Hetzer B, Tisch C, Kortekamp A, Nick P (2023) Surface wax in the ancestral grapevine Vitis sylvestris correlate with partial resistance to Powdery Mildew. BMC Plant Biology 23, 304
Gajjar P, Ismail A, Islam T, Darwish AG, Moniruzzaman MD, Abuslima E, Dawood AS, El-Saady AKM, Tsolova V, Nick P, Sherif SM, Abazinge MD, El-kereamy A, El-Sharkawy I (2023) Physiological Comparison of Two Salt-Excluder Hybrid Grapevine Rootstocks Under Salinity Reveals Differential Adaptation Quality. Plants 12, 324.
Tisch C, Kortekamp A, Nick P (2024) Searching new targets for the control of Black Rot: following the role of host factors modulating the infection process of Phyllosticta ampelicida. Plant Biology 26, 292-304
Nick P (2023) Towards a Grammar of Plant Stress – Modular Signalling Conveys Meaning. Theor Exp Plant Physiol. doi 10.1007/s40626-023-00292-2
