Calculation of United Quality Latent Indices of Deschampsia antarctica plants adaptability of different origin grown in vitro

The research was to develop and describe in detail the algorithm for calculating the United Quality Latent Index (UQLI, Iq ) of plant adaptability from the collection of Deschampsia antarctica Ė. Desv. genotypes obtained from seeds collected at different sites in the Argentine Islands region, the maritime Antarctic, and grown in vitro at the laboratory conditions. Genome size and genetic distances by ISSR and IRAP markers according to data from published articles were used as basic indices of initial genetic heterogeneity for analyzed plant genotypes. To assess individual adaptability indices for eleven D. antarctica genotypes, we used measurement of the leaf length morphometric index and determination of the flavonoids content by rutin and the content of photosynthetic pigments. The spectra of reserve and protective proteins in leaves were investigated by polyacrylamide gel electrophoresis. To obtain the United Quality Latent Index of Adaptability (Iqi, UQLI), the method of extreme grouping was used. The estimation of Iqi (UQLI) was performed using pairwise comparisons of indices from differences sets for each pair of genotypes. We developed and described in detail the algorithm for Iqi estimation for eleven D. antarctica genotypes. As an example of application, correlation models of probability relations of the indices are presented. To evaluate the complex adaptability for eleven D. antarctica genotypes grown in vitro we used developed algorithm for the UQLI calculation. The individuality of the adaptive portrait for all studied genotypes under in vitro cultivation conditions was shown. The influence of basic genetic characteristics (genome size and genetic distances) on auxin metabolism-related indices of leaf length and flavonoid content was shown. Such effect may be carried out by genetic characteristics both individually and together, probably via auxin metabolism. Among the eight genotypes researched, we distinguish four different variants by correlation models and two (positive and negative) by the general Iqi value. Thus the Iqi (UQLI) is proposed to describe a large number of source data at different organization levels which characterize sample genotypes by reducing the dimensions to one dimensionless number. This genotypes’ individuality and the peculiarities of their grouping by Iqi should be taken into account when doing experimental studies using these genotypes as model plants, especially in experiments studying the regulation of productivity and the effect of the various exogenous factors, etc.

A role of DAO1 in oxidation of IAA amino acid conjugates revealed through metabolite, high throughput transcript and protein level analysis

SummaryAuxin metabolism is, together with auxin transport, a key determinant of auxin signalling output in plant cells, yet details on the underlying mechanisms and factors involved are still largely unknown. Processes involved in the auxin metabolism are subject to regulation based on numerous signals, including auxin concentration itself. Altered auxin availability and the subsequent changes of auxin metabolite profiles can therefore elucidate the function and regulatory role of individual elements in the auxin metabolic machinery.After analysing auxin metabolism in auxin dependent tobacco BY-2 cell line grown in presence or absence of synthetic auxin 2,4-D we found that both conditions were similarly characterized by very low levels of endogenous indole-3-acetic acid (IAA) and its metabolites. However, metabolic profiling after exogenous application of IAA uncovered that the concentration of N-(2-oxindole-3-acetyl)-L-aspartic acid (oxIAA-Asp), the most abundantly formed auxin metabolite in the control culture, dramatically decreased in auxin-starved conditions. To describe the molecular mechanism behind this regulation, we analysed transcriptome and proteome changes caused by auxin starvation. While no changes in the expression of auxin biosynthetic machinery were observed, many genes related to auxin conjugation and degradation showed differential expression. Selected putative auxin glycosylating enzymes as well as members of the Gretchen Hagen 3 gene family involved in auxin amino acid conjugation showed both up- and down-regulation. Contrarily to that, all tobacco homologs of Arabidopsis thaliana DIOXYGENASE FOR AUXIN OXIDATION 1 (DAO1), known to be responsible for the formation of oxIAA from IAA, showed significant downregulation at both transcript and protein levels. To validate the role of DAO1 in auxin metabolism, we performed auxin metabolite profiling in BY-2 mutants carrying either siRNA-silenced or CRISPR-Cas9-mutated NtDAO1, as well as in dao1-1 Arabidopsis thaliana plants. Both mutants showed not only expectedly lower levels of oxIAA, but also significantly lower abundance of oxidated amino acid conjugates of IAA (oxIAA-Asp). Our results thus represent the first direct evidence on DAO1 activity on IAA amino acid conjugates.Statement of significanceHere we present an analysis of auxin metabolism on metabolite, transcript and protein levels in tobacco BY-2 cell line, collectively identifying oxidation of IAA amino acid conjugates as a new role of DIOXYGENASE FOR AUXIN OXIDATION 1 within an auxin-level-responsive metabolic system.