Medicago truncatula CORYNE regulates inflorescence meristem branching, nutrient signaling, and arbuscular mycorrhizal symbiosis
Authors: Johnathan Orosz, Erica Xinlei Lin, Penelope Lindsay, Mikayla Kappes, Sagar Bashyal, Hasani Everett, Chandan Kumar Gautam, David Jackson, Lena Mueller
Venue: bioRxiv
Published: 2024
The CLAVATA signaling pathway regulates plant development and plant-environment interactions. CLAVATA signaling consists of mobile, cell-type or environment-specific CLAVATA3/ESR-related (CLE) peptides, which are perceived by a receptor complex consisting of leucine-rich repeat receptor-like kinases such as CLAVATA1 and receptor-like proteins such as CLAVATA2, which often functions with the pseudokinase CORYNE (CRN). CLAVATA signaling has been extensively studied in various plant species for its role in meristem maintenance and in legumes for modulating root interactions with nitrogen-fixing rhizobia. Some signaling proteins involved in development and nodulation, including CLAVATA1, also regulate plant interactions with mutualistic arbuscular mycorrhizal (AM) fungi. However, our knowledge on AM symbiosis regulation by CLAVATA signaling remains limited and only a handful of genetic regulators have been identified. Here we report that Medicago truncatula CRN controls inflorescence meristem branching and negatively regulates root interactions with AM fungi. MtCRN functions partially independently of the AM autoregulation signal MtCLE53. Transcriptomic data revealed that crn roots display signs of perturbed signaling related to a range of responses to biotic and abiotic factors, suggesting that MtCRN plays various roles in plant development and interactions with the environment.
Cultivating potential: Harnessing plant stem cells for agricultural crop improvement
Authors: Penelope Lindsay, Kyle W. Swentowsky, David Jackson
Venue: Molecular Plant
Published: 2024
Meristems are stem cell-containing structures that produce all plant organs and are therefore important targets for crop improvement. Developmental regulators control the balance and rate of cell divisions within the meristem. Altering these regulators impacts meristem architecture and, as a consequence, plant form. In this review, we discuss genes involved in regulating the shoot apical meristem, inflorescence meristem, axillary meristem, root apical meristem, and vascular cambium in plants. We highlight several examples showing how crop breeders have manipulated developmental regulators to modify meristem growth and alter crop traits such as inflorescence size and branching patterns. Plant transformation techniques are another innovation related to plant meristem research because they make crop genome engineering possible. We discuss recent advances on plant transformation made possible by studying genes controlling meristem development. Finally, we conclude with discussions about how meristem research can contribute to crop improvement in the coming decades.
View Publication(DOI: 10.1016/j.molp.2023.12.014)Distinct ankyrin repeat subdomains control VAPYRIN locations and intracellular accommodation functions during arbuscular mycorrhizal symbiosis
Authors: Penelope L. Lindsay, Sergey Ivanov, Nathan Pumplin, Xinchun Zhang, Maria J. Harrison
Venue: Nature Communications
Published: 2022
Over 70% of vascular flowering plants engage in endosymbiotic associations with arbuscular mycorrhizal (AM) fungi. VAPYRIN (VPY) is a plant protein that is required for intracellular accommodation of AM fungi but how it functions is still unclear. VPY has a large ankyrin repeat domain with potential for interactions with multiple proteins. Here we show that overexpression of the ankyrin repeat domain results in a vpy-like phenotype, consistent with the sequestration of interacting proteins. We identify distinct ankyrin repeats that are essential for intracellular accommodation of arbuscules and reveal that VPY functions in both the cytoplasm and nucleus. VPY interacts with two kinases, including DOES NOT MAKE INFECTIONS3 (DMI3), a nuclear-localized symbiosis signaling kinase. Overexpression of VPY in a symbiosis-attenuated genetic background results in a dmi3 -like phenotype suggesting that VPY negatively influences DMI3 function. Overall, the data indicate a requirement for VPY in the nucleus and cytoplasm where it may coordinate signaling and cellular accommodation processes.
View Publication(DOI: 10.1038/s41467-022-32124-3)Next Generation Cereal Crop Yield Enhancement: From Knowledge of Inflorescence Development to Practical Engineering by Genome Editing
Authors: Lei Liu, Penelope L. Lindsay, David Jackson
Venue: International Journal of Molecular Sciences
Published: 2021
Artificial domestication and improvement of the majority of crops began approximately 10,000 years ago, in different parts of the world, to achieve high productivity, good quality, and widespread adaptability. It was initiated from a phenotype-based selection by local farmers and developed to current biotechnology-based breeding to feed over 7 billion people. For most cereal crops, yield relates to grain production, which could be enhanced by increasing grain number and weight. Grain number is typically determined during inflorescence development. Many mutants and genes for inflorescence development have already been characterized in cereal crops. Therefore, optimization of such genes could fine-tune yield-related traits, such as grain number. With the rapidly advancing genome-editing technologies and understanding of yield-related traits, knowledge-driven breeding by design is becoming a reality. This review introduces knowledge about inflorescence yield-related traits in cereal crops, focusing on rice, maize, and wheat. Next, emerging genome-editing technologies and recent studies that apply this technology to engineer crop yield improvement by targeting inflorescence development are reviewed. These approaches promise to usher in a new era of breeding practice.
View Publication(DOI: 10.3390/ijms22105167)Rapid expression of COVID-19 proteins by transient expression in tobacco
Authors: Penelope Lindsay, Amanda Ackerman, Yinan Jian, Oliver Artz, Daniele Rosado, Tara Skopelitis, Munenori Kitagawa, Ullas V. Pedmale, David Jackson
Venue: bioRxiv
Published: 2020
In 2020 we suffered from a major global pandemic caused by the SARS-CoV-2 coronavirus. Efforts to contain the virus include the development of rapid tests and vaccines, which require a ready supply of viral proteins. Here we report the production of two SARS-CoV-2 proteins by transient transformation of tobacco, leading to high expression within three days, and subsequent purification of the intact proteins. Such efforts may help to develop testing resources to alleviate the major impacts of this global pandemic.
A Phosphate-Dependent Requirement for Transcription Factors IPD3 and IPD3L During Arbuscular Mycorrhizal Symbiosis in Medicago truncatula
Authors: Penelope L. Lindsay, Brandon N. Williams, Allyson MacLean, Maria J. Harrison
Venue: Molecular Plant-Microbe Interactions
Published: 2019
During arbuscular mycorrhizal (AM) symbiosis, activation of a symbiosis signaling pathway induces gene expression necessary for accommodation of AM fungi. Here, we focus on pathway components Medicago truncatula INTERACTING PROTEIN OF DOES NOT MAKE INFECTIONS 3 (IPD3) and IPD3 LIKE (IPD3L), which are potential orthologs of Lotus japonicus CYCLOPS, a transcriptional regulator essential for AM symbiosis. In the double mutant ipd3 ipd3l, hyphal entry through the epidermis and overall colonization levels are reduced relative to the wild type but fully developed arbuscules are present in the cortex. In comparison with the wild type, colonization of ipd3 ipd3l is acutely sensitive to higher phosphate levels in the growth medium, with a disproportionate decrease in epidermal penetration, overall colonization, and symbiotic gene expression. When constitutively expressed in ipd3 ipd3l, an autoactive DOES NOT MAKE INFECTIONS 3 induces the expression of transcriptional regulators REDUCED ARBUSCULAR MYCORRHIZA 1 and REQUIRED for ARBUSCULE DEVELOPMENT 1, providing a possible avenue for arbuscule development in the absence of IPD3 and IPD3L. An increased sensitivity of ipd3 ipd3l to GA3 suggests an involvement of DELLA. The data reveal partial redundancy in the symbiosis signaling pathway, which may ensure robust signaling in low-phosphorus environments, while IPD3 and IPD3L maintain signaling in higher-phosphorus environments. The latter may buffer the pathway from short-term variation in phosphorus levels encountered by roots during growth in heterogeneous soil environments.
View Publication(DOI: 10.1094/MPMI-01-19-0006-R)