Jens frackenpohl biography

Abstract

Climate change and overexploitation of groundwater resources cause constraints on water demand for agriculture, thus threatening crop productivity. For future food security, there is an urgent need for crops of high water use efficiency combined with high crop productivity, i.e. having high water productivity. High water productivity means efficient biomass accumulation at reduced transpiration. Recent studies show that plants are able to optimize carbon uptake per water transpired with little or no trade-off in yield. The phytohormone abscisic acid (ABA) plays a pivotal role in minimizing leaf transpiration and mediating enhanced water productivity. Hence, ABA and more chemically stable ABA agonists have the potential to improve crop water productivity. Synthesis, screening, and identification of suitable ABA agonists are major efforts currently undertaken. In this study, we used yeast expressing the plant ABA signal pathway to prescreen ABA-related cyano cyclopropyl compounds (CCPs). The yeast analysis allowed testing the ABA agonists for general toxicity, efficient uptake, and specificity in regulating different ABA receptor complexes. Subsequently, promising ABA-mimics were analyzed in vitro for ligand-receptor interaction complemented by physiological analyses. Several CCPs activated ABA signaling in yeast and plant cells. CCP1, CCP2, and CCP5 were by an order of magnitude more efficient than ABA in minimizing transpiration of Arabidopsis plants. In a progressive drought experiment, CCP2 mediated an increase in water use efficiency superior to ABA without trade-offs in biomass accumulation.

Keywords: ABA, ABA receptor, Arabidopsis, cyano cyclopropyl ABA analog, drought, transpiration, water use efficiency, wheat

Introduction

Plants produce biomass using conversion of solar radiation into chemically stored energy by recruiting CO₂ and water (Barber, 2009). The influx of atmospheric CO₂ and the efflux of water vapor at the leaf surface sha

Introduction

Plants produce biomass using conversion of solar radiation into chemically stored energy by recruiting CO₂ and water (Barber, 2009). The influx of atmospheric CO₂ and the efflux of water vapor at the leaf surface share the same stomatal diffusion path (Franks et al., 2013), which inherently links CO₂ assimilation to water vapor loss (Farquhar et al., 1989). The low abundance and the shallow gradient of CO₂ across the stomata compared to water vapor gradients lead to exhaustive water vapor mobilization of soil-borne water into the atmosphere during CO₂ uptake. Unlike the ubiquity of CO₂, replenishment of freshwater resources by rainfall and aquifers varies on a large spatial and temporal scale (Rodell et al., 2018). Climate change and overexploitation of groundwater resources are expected to exacerbate the current non-sustainable water use in agriculture (Rodell et al., 2018). On a global scale, water scarcity is the dominant cause for yield losses in crops (FAO, 2021). To maintain or increase current crop productivity, there is an urgent need for water-use-efficient crops.

Water use efficiency (WUE) refers to carbon capture per unit of water consumed, however, there are several WUE levels referring to seed yield, biomass, or gas exchange (Morison et al., 2008; Blum, 2009). The ratio of net assimilation rate to stomatal conductance, the so-called intrinsic WUE (iWUE) of leaves, changes if water becomes limiting. In C3 plant species, iWUE increases by approximately two-fold during transition from well-watered conditions to dry soil (Rizza et al., 2012; Blankenagel et al., 2018). The increase is due to an appreciable reduction in transpiration while carbon capture and net photosynthesis are less negatively affected. Transpiration is reduced by diminishing stomatal aperture, which in turn, is primarily regulated by the phytohormone ABA (Raghav

University of Groningen, Holland

Ben L. Feringa obtained his PhD degree at the University of Groningen in the Netherlands under the guidance of Professor Hans Wynberg. After working as a research scientist at Shell in the Netherlands and the UK, he was appointed lecturer and in 1988 full professor at the University of Groningen and named the Jacobus H. van 't Hoff Distinguished Professor of Molecular Sciences in 2004. He was elected Foreign Honorary member of the American Academy of Arts and Sciences. He is a member of the Royal Netherlands Academy of Sciences. In 2008 he was appointed Academy Professor and he was knighted by Her Majesty the Queen of the Netherlands. Feringa’s research has been recognized with numerous awards including the Körber European Science Award (2003), the Spinoza Award (2004), the Prelog gold medal (2005), the Norrish Award of the ACS (2007), the Paracelsus medal (2008), the Chirality medal (2009), the RSC Organic Stereochemistry Award (2011), the Humboldt award (2012), the Nagoya gold medal (2013), the ACS Cope Scholar Award (2015), the Chemistry for the Future Solvay Prize (2015), the August-Wilhelm-von-Hoffman Medal (2016), The 2016 Nobel prize in Chemistry, the Tetrahedron Prize (2017) and the European Chemistry Gold Medal (2018). In 2019 he was elected as a member of the European Research Council. Feringa’s research interest includes stereochemistry, organic synthesis, asymmetric catalysis, molecular switches and motors, self-assembly, molecular nanosystems and photopharmacology.