Longyun Guo's research while affiliated with Purdue University and other places

Publications (15)

Article
Lignin, one of the most abundant polymers in plants, is derived from the phenylpropanoid pathway, which also gives rise to an array of metabolites that are essential for plant fitness. Genetic engineering of lignification can cause drastic changes in transcription and metabolite accumulation with or without an accompanying development phenotype. To...
Article
Out of the three aromatic amino acids, the highest flux in plants is directed towards phenylalanine, which is utilized to synthesize proteins and thousands of phenolic metabolites contributing to plant fitness. Phenylalanine is produced predominantly in plastids via the shikimate pathway and subsequent arogenate pathway, both of which are subject t...
Article
Full-text available
In plants, phenylalanine biosynthesis occurs via two compartmentally separated pathways. Overexpression of petunia chorismate mutase 2 (PhCM2), which catalyzes the committed step of the cytosolic pathway, increased flux in cytosolic phenylalanine biosynthesis, but paradoxically decreased the overall levels of phenylalanine and phenylalanine-derived...
Article
Mathematical modeling of plant metabolism enables the plant science community to understand the organization of plant metabolism, obtain quantitative insights into metabolic functions, and derive engineering strategies for manipulation of metabolism. Among the various modeling approaches, metabolic pathway analysis can dissect the basic functional...
Article
Full-text available
In addition to being a vital component of proteins, phenylalanine is also a precursor of numerous aromatic primary and secondary metabolites with broad physiological functions. In plants phenylalanine is synthesized predominantly via the arogenate pathway in plastids. Here, we describe the structure, molecular players and subcellular localization o...
Article
Lignin is a polymer that significantly inhibits saccharification of plant feedstocks. Adjusting the composition or reducing the total lignin content have both been demonstrated to result in an increase in sugar yield from biomass. However, because lignin is essential for plant growth, it cannot be manipulated with impunity. Thus, it is important to...
Article
Full-text available
Background Metabolic fluxes represent the functional phenotypes of biochemical pathways and are essential to reveal the distribution of precursors among metabolic networks. Although analysis of metabolic fluxes, facilitated by stable isotope labeling and mass spectrometry detection, has been applied in the studies of plant metabolism, we lack exper...
Article
We analyze the sample complexity of a new problem: learning from a sequence of experiments. In this problem, the learner should choose a hypothesis that performs well with respect to an infinite sequence of experiments, and their related data distributions. In practice, the learner can only perform m experiments with a total of N samples drawn from...
Article
Detrimental effects of hyperaccumulation of the aromatic amino acid phenylalanine (Phe) in animals, known as phenylketonuria, are mitigated by excretion of Phe derivatives; however, how plants endure Phe accumulating conditions in the absence of excretion system is currently unknown. To achieve Phe hyperaccumulation in a plant system, we simultaneo...
Article
Full-text available
In addition to proteins, L-phenylalanine is a versatile precursor for thousands of plant metabolites. Production of phenylalanine-derived compounds is a complex multi-compartmental process using phenylalanine synthesized predominantly in plastids as precursor. The transporter(s) exporting phenylalanine from plastids, however, remains unknown. Here,...

Citations

... As a crucial precursor to the production of phenolic compounds, phenylalanine is produced predominantly in plastids via the shikimate pathway and is subsequently utilized to synthesize thousands of phenolic metabolites through the phenylpropanoid biosynthesis pathway [30]. Here, to visualize the molecular switches controlling phenylalanine formation and conversion, the partial metabolic pathways of the shikimate pathway and phenylpropanoid biosynthesis and the heat map of expression profiles of DEGs associated with these two pathways were generated ( Figure 5). ...
... While KAT1 and KAT3 are phylogenetically related with each other, KAT2 is closely related to aminoadipate AT and KAT4 to aspartate AT, which gained KAT activity (Fig. 3). Arabidopsis plants also have at least three different tryptophan AT isoforms having specific roles: TAA1, TAR1, and TAR2 generate indole-3pyruvate, the precursor of auxin, in certain developmental stages or tissue types ( Fig. 2) (91)(92)(93)(94). ...
... Computational modeling of PSM allows the quantitative understanding of metabolic functions and development of engineering strategies to optimize the PSM production (Clark et al., 2020). Incomplete characterization of PSM genes and redundancy of pathway functions pose a significant challenge for building reliable metabolic models for rational metabolic engineering. ...
... Line Eng-2, which showed higher 4-HBA titers compared to Eng-1, could be further engineered to enhance 4-HBA content. Possible strategies include the additional expression of UbiC targeted to the cytosol where its substrate chorismate is also located (Qian et al., 2019;Sommer and Heide, 1998), and the expression of the recently discovered p-hydroxybenzoyl-CoA monolignol transferase to promote the attachment of readily cleavable 4-HBA esters onto lignin in cell walls (de Vries et al., 2022;Zhao et al., 2021). Considering the slight yield penalty observed in line Eng-2 under field conditions, the 4-HBA co-product trait developed in this line should be introgressed into high-yielding biomass sorghum varieties (Olson et al., 2012). ...
... The increased phenylalanine levels are indicative of the induction of the phenylpropanoid pathway, an epicenter of defense-related metabolites [10]. Phenylalanine is thus regarded as a key metabolite that serves as a bridge between the phenylalanine metabolism to other specialized metabolic pathways, as it serves as a precursor of secondary metabolites, such as flavonoids, alkaloids, and phenylpropanoids, and as a stress-related signal [56][57][58]. ...
... Previous acetate incorporation studies have primarily focused on metabolites involved in lipid biosynthesis in only a few plant species. In these studies, acetate was used in low concentrations as a tracer, not as a carbon source (Supplementary Table 4) [34][35][36] . To investigate acetate utilization as a carbon source, we grew undifferentiated lettuce tissue (callus) (to avoid the carbon and energy stored in seeds) in the dark in liquid media containing effluent (0.691 M acetate: 1 M KOH) and added in 13 C-acetate to enable tracking of carbon incorporation. ...
... The cationic amino acid transporters (CATs) play important roles in various biological process including plant growth and development along with resistance to abiotic stresses. Several CATs have been identified in Arabidopsis thaliana [2,15], Solanum lycopersicum [25,26], petunia hybrid [27,28], Populus tremula [18] and Oryza sativa [19] previously. However, cotton was still lacking any type of studies about CATs. ...
... The cationic amino acid transporters (CATs) play important roles in various biological process including plant growth and development along with resistance to abiotic stresses. Several CATs have been identified in Arabidopsis thaliana [2,15], Solanum lycopersicum [25,26], petunia hybrid [27,28], Populus tremula [18] and Oryza sativa [19] previously. However, cotton was still lacking any type of studies about CATs. ...