Prof. Sean Cutler and colleagues at the University of California, Riverside have engineered a system and methods to induce gene expression in plants and organisms, including mammals, using the chemical compound mandipropamid. Using the PYR/PYL/HAB1 promoter system, the PYR1/HAB1 system is reprogrammed to be activiated with mandipropamid.  When the PYR1/HAB1 system dimerizes through chemical induced dimerization (CID) with mandipropamid, the system functions as a control switch for gene expression. This technology has been demonstrated to advantageously accelerate citrus breeding.  It may be applied to improve CAR T-cell therapy and agricultural crops. Fig 1: UCR’s PYR1/HAB1 system is programmed through chemical induced dimerization (CID) initiated by mandipropamid to function as a switch for agrochemical control of gene expression.  

In this invention, gene-editing of EPFL10 and STOMAGEN using CRISPR/Cas9 in cv. Nipponbare reduces stomatal density while maintaining photosynthesis and enhancing water conservation in rice, yielding lines with c. 80% and 25% of wild-type stomata, respectively. Rice plants with small reductions in stomatal densities are able to conserve water to similar extents as rice plants with large stomatal density reductions but do not suffer from any concomitant reductions in stomatal conductance, carbon assimilation, or thermoregulation. Rice production is of paramount importance for global nutrition and will be detrimentally affected by climate change.   

Prof. Hailing Jin and colleagues from the University of California, Riverside have identified genetic negative immune regulators that control the natural immune responses in citrus against HLB. Decreasing or removing these immune regulators may lead to citrus plants that are tolerant and/or resistance to HLB. The development of HLB resistant citrus plants is less expensive and a more efficient long term solution compared to current HLB management strategy, which includes removing infected trees and/or applying pesticides to lower the ACP population. Fig 1:Nicotiana benthamiana (Nb) model plants after exposure to HLB-like infection for 5 days. The plant with its VAD gene knocked-down (siVAD) expresses resistance to the HLB-like infection. The control plant (iRB control) is pictured on the left and is less resistant to the HLB-like infection. 

Researchers at the University of California, Davis have identified specific genetic modifications to plants that impart a variety of advantages based on modulating the presence of suberin

Researchers at the University of California, Davis have developed a method that increases salt tolerance in plants. This method introduces a polynucleotide that encodes a Na+/H+ transporter polypeptide.

Researchers at the University of California, Davis have developed a pepper plant that abscises its pedicel easily during harvesting, also known as destemming or decapping.

Prof. Kaloshian and her colleagues from the University of California, Riverside, have developed plants with enhanced immunity resulting in enhanced resistance to RKNs. The methods comprise introducing into a plant a gene editing construct that specifically inhibits activity of G-LecRK-VI.13 gene, a negative regulator of plant immunity. Additionally, the descendant of this plant also carry the enhanced resistance to RKNs. The invention could be used in a broad range of important agricultural crops including rice, lettuce, and tomatoes. This approach holds potential for increasing crop quality and yield, considering that plant damage from RKNs result in poor growth, a decline in quality and yield of the crop, and reduced resistance to environmental stresses. By triggering an enhanced immune response, by eliminating a negative regulator of immunity, the opportunity exists to develop more durable plant resistance towards RKNs and other types of nematodes.  Fig 1: Tomato plants, grown in a plastic house, infected with the root-knot nematode Meloidogyne incognita.  

The response of plants to reduced water availability is controlled by a complex osmotic stress and abscisic acid (ABA)-dependent signal transduction network. The core ABA signaling components are snf1-related protein kinase2s (SnRK2s) which are activated by ABA-dependent inhibition of type 2C protein phosphatases and by an unknown ABA-independent osmotic stress signaling pathway. Limited water availability is one of the key factors that negatively impacts crop yields. The plant hormone abscisic acid (ABA) and the signal transduction network it activates, enhance plant drought tolerance through stomatal closure, and inhibition of seed germination and growth. As plants are constantly exposed to changing water conditions, reversibility and robustness of the ABA signal transduction cascade is important for plants to balance growth and drought stress resistance. Core ABA signaling components have been established the ABA receptors PYRABACTIN RESISTANCE (PYR/PYL) or REGULATORY COMPONENT OF ABA RECEPTOR (RCAR) inhibit type 2C protein phosphatases (PP2Cs) resulting in the activation of the SnRK2 protein kinases SnRK2.2, 2.3 and OST1/SnRK2.6 . However, it has remained unclear whether direct autophosphorylation or trans-phosphorylation by unknown protein kinases re-activates these SnRK2 protein kinases in response to stress. The osmotic stress sensing mechanism and upstream signal transduction mechanisms leading to SnRK2 activation remain largely unknown in plants.

University of California, Riverside researcher Prof. Hailing Jin and her colleagues have developed plants that are resistant to Botrytis cineria. These plants are genetically engineered to silence fungal pathogens that transfer “virulent” small RNA effectors to the plant that cause disease.  This has led to the development of plants that are resistant to Botrytis cineria. Fig. 1 shows that transgenic plants exhibited reduced disease susceptility to Botrytis cineria when compared with the wild type. Fig. 2 shows that lesion size and fungal biomass of at least 20 leaves were reduced in the transgenic plant when compared to the wild type. Measurements were take at 96 hours after exposure to Botrytis cineria.    

Researchers at the University of California, Davis and the Institute of Molecular and Cellular Biology of Rosario in Argentina have collaborated to develop methods for improving plant regeneration efficiency using transformations via a GRF, a GIF, or a GRF-GIF chimera. 

Mutated versions of Cas12a that remove its non-specific ssDNA cleavage activity without affecting site-specific double-stranded DNA cutting activity. These mutant proteins, in which a short amino acid sequence is deleted or changed, provide improved genome editing tools that will avoid potential off-target editing due to random ssDNA nicking.

Researchers at the University of California have identified new modified versions of the carbon fixing enzyme, Phosphoenolpyruvate carboxylase (PPC).  in planta results show that the modified PPC enzymes confer upwards of a five fold increase in carbon fixation when compared to wild type plants. PPC dependent carbon fixation is key to photosynthesis, production of nutrients, and plants conditioning their growth environment. Plants with modified PPCs that increase carbon fixation and photosynthetic output will have increased plant productivity, which is critical for feeding a growing population. Additionally, by identifying surgical changes that can unleash the full productivity of plant PPC’s, it will be possible to increase the rate of depletion of atmospheric CO2.  The combination of these outcomes represents the opportunity to boost agricultural productivity, increase the amount of agriculturally available land by upwards of 100%, and improve the nutritional quality of plants all of which are dependent on removal of CO2 from our atmosphere.  Fig. 2 in vitro comparison of wild type (wt) and modified versions of maize PPC1, which is key to C4 photosynthesis, in the absence or presence of increasing amounts of the allosteric inhibitor, malate. Whereas version A is less affected by malate than wt, both versions B and C are largely unaffected by malate and have a 2-fold increase in activity compared to the wt version.  

Researchers at the University of California, Davis have developed a method to produce haploid progeny plants from transgenic and wild-type plants that only carry chromosomes from the wild-type gamete.

Researchers at the University of California, Davis have developed a guided nuclease based expression system to introduce genetic modifications into plants without the need for tissue culture.

Researchers at the University of California, Davis have developed a method of cell-specific degradation of centromeric proteins to induce haploid.

UCLA researchers in the Department of Molecular, Cell, and Developmental Biology have developed a method to specifically suppress the highly efficient non-homologous end joining (NHEJ) pathway to boost homologous recombination efficiency in plants.

Brief description not available

Background: Brassinosteroids are essential plant hormones that control growth and development, in addition to playing a critical role in response to stress and infections. Brassinosteroids also induce ethylene synthesis and are therefore related to senescence and ripening. The major overarching issue involves strictly controlling brassinosteroid response in order to promote growth yet limit other negative effects of brassinosteroids.  Brief Description: UCR researchers have identified three compounds that alter brassinosteroid signaling in plants. These chemicals were found to increase the effects of limited brassinosteroids found under normal conditions yet reduce the effects of excess brassinosteroids. This includes promotive effects on plant height, which increase by 100% due to the chemical enhancing the impact of endogenous brassinosteroids. In contrast, the extreme effects seen with addition of high levels of brassinosteroids are substantially reduced upon addition of this chemical, indicating that this chemical may be useful for modulating the effects of brassinosteroids. In conjunction with this, treatment with the chemical resulted in reversal of several ethylene dependent growth phenomena that are also regulated by brassinosteroids. Currently, there is a huge unmet need in the agricultural sector since treatments that modulate brassinosteroid-regulated phenomena do not exist.

Background: California is one of the largest citrus producers in the world, and the demand for fresh citrus fruit that is seedless or low-seeded is on the rise. ‘Kinnow’ is the currently popular mandarin cultivar that covers 80% of all citrus trees in the Middle Eastern regions. Despite its fecundity in this region, it is very seedy and contains about 15-30 seeds per fruit. Therefore, there is high demand for mandarins that can not only withstand diverse climate conditions but have a low seed count.  Brief Description: ‘KinnowLS’ is a mandarin selection developed by mutation breeding of the diploid mandarin cultivar ‘Kinnow’, having only two to three seeds per fruit in all situations of cross-pollination. It is a mid- to late-season maturing diploid mandarin that combines large-sized fruit of excellent quality and production with low seed content even in mixed plantings. ‘KinnowLS’ exhibits vertical tree growth habits, which allows it to produce a large and dense crown. This novel hybrid could be successful in a mid-to-late season marketing window which currently has few low-seeded, high quality cultivars.

Background: Due to the rapidly increasing demand of food production, agricultural biotechnology companies are aiming to improve crop productivity. Biotechnology tools that develop novel plant traits are projected to have a $1.3B global market with annual growth of 49.9% by 2019.  Brief Description: UCR Researchers have developed a drug-like compound, HTC, that is structurally distinct from other agrochemicals and will rapidly induce an immune response in plants to ward off pathogens. Only a small dose of this novel compound is needed for optimal protection as well as growth enhancement. By genetically engineering the plant to have a stronger inherent immune system, toxic chemicals like pesticides are no longer needed to protect the plant. Its implementation can render decreased usage of agrochemicals that are harmful to humans and the environment.

Brief description not available

Brief description not available

Researchers at UC Davis have produced a non-dormant alfalfa line highly amenable to transformation, allowing direct improvement of the line. Higher transformation efficiency and a non-dormant life-cycle make this line of alfalfa a valuable tool for research and breeding.

Background: Citrus greening disease, also known as huanglongbing (HLB), has been a serious, pervasive problem caused by a multitude of plant pathogens. It has decimated many citrus trees, drastically decreasing orange production and costing the US economy an estimated $11B every year. Currently, there is no cure for HLB, so the citrus industry is in dire need for a cost-effective method of early HLB detection.  Brief Description: UCR Researchers have developed a means to detect and identify multiple plant pathogens for disease diagnosis, including citrus greening disease. By developing a novel multiplex RNA assay, they discovered ten targets of nine citrus pathogens and a citrus control gene. In addition to the assays, target-specific probes were designed and implemented to improve the pathogen detection process. These assays were also coupled with high-throughput robotic extraction and purification procedures, optimized for citrus tissues. Furthermore, they also developed a 3-plex DNA assay system along with 3 targets for simultaneous detection, identification and quantification of plant pathogens.

Background: Over the years, the world renowned Citrus Experiment Station became the foundation of  the UC Riverside campus, where citrus breeding and agricultural research remain at the forefront.  UCR’s premier citrus breeding program varieties are  licensed worldwide, and some have been considered by professional taste panels to be one of the best flavored citrus in the world. Description: ‘FairchildLS,’  a mandarin developed by mutation breeding, is  seedless or low-seeded in all situations of cross-pollination. It has a moderately smooth texture and a sweet, rich fruit flavor. Easy to peel and with a deep orange color, the ‘FairchildLS’ is an attractive citrus that is popular and sought-out by the citrus industry.