Aux/IAA11 Is Required for UV-AB Tolerance and Auxin Sensing in Arabidopsis thaliana

Abstract

In order to survive, plants have, over the course of their evolution, developed sophisticated acclimation and defense strategies governed by complex molecular and physiological, and cellular and extracellular, signaling pathways. They are also able to respond to various stimuli in the form of tropisms; for example, phototropism or gravitropism. All of these retrograde and anterograde signaling pathways are controlled and regulated by waves of reactive oxygen species (ROS), electrical signals, calcium, and hormones, e.g., auxins. Auxins are key phytohormones involved in the regulation of plant growth and development. Acclimation responses, which include programmed cell death induction, require precise auxin perception. However, our knowledge of these pathways is limited. The Aux/IAA family of transcriptional corepressors inhibits the growth of the plant under stress conditions, in order to maintain the balance between development and acclimation responses. In this work, we demonstrate the Aux/IAA11 involvement in auxin sensing, survival, and acclimation to UV-AB, and in carrying out photosynthesis under inhibitory conditions. The tested iaa11 mutants were more susceptible to UV-AB, photosynthetic electron transport (PET) inhibitor, and synthetic endogenous auxin. Among the tested conditions, Aux/IAA11 was not repressed by excess light stress, exclusively among its phylogenetic clade. Repression of transcription by Aux/IAA11 could be important for the inhibition of ROS formation or efficiency of ROS scavenging. We also hypothesize that the demonstrated differences in the subcellular localization of the two Aux/IAA11 protein variants might indicate their regulation by alternative splicing. Our results suggest that Aux/IAA11 plays a specific role in chloroplast retrograde signaling, since it is not repressed by high (excess) light stress, exclusively among its phylogenetic clade.

AtSNP_TATAdb: Candidate Molecular Markers of Plant Advantages Related to Single Nucleotide Polymorphisms within Proximal Promoters of Arabidopsis thaliana L.

“…On one hand, the first SNP (i.e., ENSVATH01403825:A) is the substitution “T => A” at position −33 relative to the transcription start site of ARF1-204 annotated in the Ensembl Plant database [ 31 ], such as “taaaaaaaaaTATAAAGagga => taaaaaaaaaAATAAAGagga” ( Figure 5 a, Table S1 [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , …”

“…We also described the possible effect of increased or decreased expression for another 109 genes from having SNPs in proximal promoters by the hand-curated annotation ( Table S1 ) of 83 original articles and found 173 putative advantages ( Table 1 ) such as fast growing [ 43 ], lateral root formation [ 48 ], inorganic phosphate deficiency stress response [ 52 ], antiviral response [ 59 ], photo-oxidative stress response [ 61 ], food allergenicity [ 83 ], susceptibility to parasites [ 89 ], flowering time [ 92 ], trichome number [ 97 ], plant–environment response [ 105 ], seed mineral concentrations [ 108 ], drought stress response [ 111 ], photosynthetic efficiency [ 113 ], cold tolerance [ 116 ], coenzyme Q10 concentration [ 118 ] and resistance to low-nutrient conditions [ 123 ]. These vital plant traits can vary depending on the proximal promoter SNPs, as observed experimentally in 17 crop species ( Table 1 ) such as Cymbidium goeringii [ 41 ], Triticum turgidum [ 51 ], Camellia oleifera [ 52 ], Solanum lycopersicum [ 57 ], Vitis vinifera L. [ 58 ], Oryza sativa L. [ 59 ], Carica papaya [ 60 ], Betula pendula [ 69 ] and Lilium longiflorum [ 72 ] ( Table S1 ).…”