Functional Analysis of the Arabidopsis PAL Gene Family in Plant Growth, Development, and Response to Environmental Stress1[W][OA]

By Junli Huang, Min Gu, Zhibing Lai, B. Fan, K. Shi, Yanhong Zhou, Jingquan Yu, Zhixiang Chen. Plant Physiology, 2010

877 citations recorded by the source corpus.

Phenylalanine ammonia-lyase (PAL) catalyzes the first step of the phenylpropanoid pathway, which produces precursors to a variety of important secondary metabolites. Arabidopsis (Arabidopsis thaliana) contains four PAL genes (PAL1–PAL4), but there has been no genetic analysis to assess the biological functions of the entire gene family. Here, we report the generation and analysis of combined mutations for the four Arabidopsis PAL genes. Contrary to a previous report, we found that three independent pal1 pal2 double mutants were fertile and generated yellow seeds due to the lack of condensed tannin pigments in the seed coat. The pal1 pal2 double mutants were also deficient in anthocyanin pigments in various plant tissues, which accumulate in wild-type plants under stress conditions. Thus, PAL1 and PAL2 have a redundant role in flavonoid biosynthesis. Furthermore, the pal1 pal2 double mutants were more sensitive to ultraviolet-B light but more tolerant to drought than wild-type plants. We have also generated two independent pal1 pal2 pal3 pal4 quadruple knockout mutants, which are stunted and sterile. The quadruple knockout mutants still contained about 10% of the wild-type PAL activity, which might result from one or more leaky pal mutant genes or from other unknown PAL genes. The quadruple mutants also accumulated substantially reduced levels of salicylic acid and displayed increased susceptibility to a virulent strain of the bacterial pathogen Pseudomonas syringae. These results provide further evidence for both distinct and overlapping roles of the Arabidopsis PAL genes in plant growth, development, and responses to environmental stresses.

Subfields: Molecular Biology, Plant Science

View Paper: https://www.semanticscholar.org/paper/7237b7f33e5f3e9195b308064c340a50a04cd350

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In Molecular Biology

1. C. Fraser
2. A. Abdelkhalek
3. M. Janda
4. E. Ruelland
5. C. Chapple
6. Abdulaziz Alaskar

In Plant Science

1. D. Dempsey
2. A. Vlot
3. E. Ruelland
4. M. Janda
5. A. Abdelkhalek
6. D. Klessig
7. C. Chapple
8. Abdulaziz Alaskar

Citations in the corpus

• Green Synthesized ZnO Nanoparticles Mediated by Mentha Spicata Extract Induce Plant Systemic Resistance against Tobacco Mosaic Virus (2020, background): “Beside it is the first enzyme in the phenylpropanoid pathway linking the primary and secondary metabolism [61], PAL is involved in salicylic acid (SA) biosynthesis [62].”
• The Phenylpropanoid Pathway in Arabidopsis (2011, background): “The double mutant is also deficient in tannin and anthocyanin biosynthesis (Huang et al., 2010).”
• Comprehending crystalline β-carotene accumulation by comparing engineered cell models and the natural carotenoid-rich system of citrus (2011, neutral): “Arabidopsis genome comprises four PAL genes (AtPAL1 to AtPAL4), among them AtPAL1 and AtPAL2 have a redundant role in flavonoid biosynthesis (Huang et al., 2010).”
• Magical mystery tour: Salicylic acid signalling (2015, background): “That said, the PAL pathway is also likely to contribute to pathogenic bacteria-related SA production since a pal1pal2pal3pal4 quadruple mutant exhibits a reduced amount of SA (both basal and after infection), and an increased susceptibility to Pseudomonas syringae (Huang et al., 2010).”
• Salicylic Acid Biosynthesis and Metabolism (2011, background): “Although SA levels were not substantially altered in the PAL single and double mutants (Huang et al, 2010), the impact of quadruple PAL mutations on plant metabolism would likely be much more severe.”
• Lignins: Biosynthesis and Biological Functions in Plants (2018, background): “Lignin content in Arabidopsis thaliana quadruple mutant (pal1/pal2/pal3/pal4) of PAL genes, decreased by 20–25% as compared with the wild type, while the quadruple mutant also displayed reduced levels of salicylic acid and increased susceptibility to pathogen [21].”
• The flavonoid biosynthetic pathway in Arabidopsis: structural and genetic diversity. (2013, neutral): “In fact, pal1 pal2 double mutants exhibited a reduced production of anthocyanins and proanthocyanidins [63].”