MASSUGU2 Encodes Aux/IAA19, an Auxin-Regulated Protein That Functions Together with the Transcriptional Activator NPH4/ARF7 to Regulate Differential Growth Responses of Hypocotyl and Formation of Lateral Roots in Arabidopsis thaliana

AbstractPlants enhance their growth in the presence of particular soil bacteria due to volatile compounds affecting the homeostasis of plant growth hormones. However, the mechanisms of volatile compound signaling and plant perception has been unclear. This study identifies the bioactive volatile 3-octanone as a plant growth stimulating volatile, constitutively emitted by the soil bacterium Streptomyces coelicolor grown on a rich medium. When 3-octanone is applied to developing Arabidopsis thaliana seedlings, a family-wide induction of the Kelch-repeat F-box genes known as KISS ME DEADLY (KMD) subsequently alters auxin/cytokinin homeostasis to promote the growth of lateral roots and inhibit the primary root. Loss of function of the KMD family or other alterations of auxin/cytokinin homeostasis suppresses the volatile-induced growth response. This reveals a function of KMDs in the pathway of microbial volatile perception and plant growth responses.Significance StatementVolatiles from soil microbes are profound stimulators of plant growth. This work identifies for the first time a plant hormone signaling regulator, the gene family KISS ME DEADLY (KMD), to be an early essential step in plant growth promotion by a soil bacterial volatile, 3-octanone. The KMD-regulated gene network alters the tissue sensitivity balance for the growth hormones auxin and cytokinin, modifying root growth rate and architecture. Previously, the Kelch repeat F-box gene family of KMDs have been shown to be important down-regulators of both positive cytokinin signaling and phenylpropanoid biosynthesis, but upstream cues were unknown. This report places the KMD family regulation of plant growth and defense into its biotic context.

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Utilization of a hydrate cellulose film for investigation of Arabidopsis thaliana L. root system growth and development

Biotekhnologiya ◽

10.21519/0234-2758-2020-36-1-36-43 ◽

2020 ◽

Vol 36 (1) ◽

pp. 36-43

Author(s):

I.O. Konovalova ◽

T.N. Kudelina ◽

S.O. Smolyanina ◽

A.I. Lilienberg ◽

T.N. Bibikova

Keyword(s):

Arabidopsis Thaliana ◽

Root System ◽

Life Support ◽

Higher Plants ◽

Plant Root ◽

Lateral Roots ◽

Basic Research ◽

Cellulose Film ◽

A New Technique ◽

Basic Research Project

A new technique for Arabidopsis thaliana cultivation has been proposed that combines the use of a phytogel-based nutrient medium and a hydrophilic membrane of hydrate cellulose film, separating the root system of the plant from the medium thickness. Growth rates of both main and lateral roots were faster in the plants cultivated on the surface of hydrate cellulose film than in the plants grown in the phytogel volume. The location of the root system on the surface of the transparent hydrate film simplifies its observation and analysis and facilitates plant transplantation with preservation of the root system configuration. The proposed technique allowed us to first assess the effect of exogenous auxin on the growth of lateral roots at the 5-6 developmental stage. methods to study plant root systems, hydrate cellulose film, A. thaliana, lateral roots, differential root growth rate, auxin The work was financially supported by the Russian Foundation for Basic Research (Project Bel_mol_a 19-54-04015) and the basic topic of the Russian Academy of Sciences - IBMP RAS «Regularities of the Influence of Extreme Environmental Factors on the Processes of Cultivation of Higher Plants and the Development of Japanese Quail Tissues at Different Stages of its Ontogenesis under the Conditions of Regenerative Life Support Systems».

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Differential Growth Responses of Wheat Seedlings to Elevated CO2

Notulae Scientia Biologicae ◽

10.15835/nsb10310286 ◽

2018 ◽

Vol 10 (3) ◽

pp. 400-409 ◽

Cited By ~ 3

Author(s):

Hamid Reza ESHGHIZADEH ◽

Morteza ZAHEDI ◽

Samaneh MOHAMMADI

Keyword(s):

Leaf Area ◽

Plant Height ◽

Elevated Co2 ◽

Co2 Concentration ◽

Tolerance Index ◽

Dry Matter Accumulation ◽

Wheat Cultivars ◽

Growth Responses ◽

Differential Growth ◽

Wheat Seedlings

Intraspecific variations in wheat growth responses to elevated CO2 was evaluated using 20 Iranian bread wheat (Triticum aestivum L.) cultivars. The plants were grown in the modified Hoagland nutrient solution at a greenhouse until 35 days of age using two levels of CO2 (~380 and 700 µmol mol–1). The shoot and root dry weights of the wheat cultivars exhibited average enhancements of 17% and 36%, respectively, under elevated CO2. This increase was associated with higher levels of chlorophyll a (25%), chlorophyll b (21%), carotenoid (30%), leaf area (54%) and plant height (49.9%). The leaf area (r = 0.69**), shoot N content (r = 0.62**), plant height (r = 0.60**) and root volume (r = 0.53*) were found to have important roles in dry matter accumulation of tested wheat cultivars under elevated CO2 concentration. However, responses to elevated CO2 were considerably cultivar-dependent. Based on the stress susceptibility index (SSI) and stress tolerance index (STI), the wheat cultivars exhibiting the best response to elevated CO2 content were ‘Sistan’, ‘Navid’, ‘Shiraz’, ‘Sepahan’ and ‘Bahar’, while the ones with poor responses were ‘Omid’, ‘Marun’, ‘Sorkhtokhm’ and ‘Tajan’. The findings from the present experiment showed significant variation among the Iranian wheat cultivars in terms of their responses to elevated air CO2, providing the opportunity to select the most efficient ones for breeding purposes.

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Allocation of added selenium in lettuce and its impact on roots

Agricultural and Food Science ◽

10.23986/afsci.5754 ◽

2003 ◽

Vol 12 (3-4) ◽

pp. 155-164 ◽

Cited By ~ 14

Author(s):

A. SIMOJOKI ◽

T. XUE ◽

K. LUKKARI

Keyword(s):

Root Morphology ◽

Specific Volume ◽

Dry Matter ◽

Lateral Roots ◽

Large Scatter ◽

Growth Responses ◽

Endogenous Ethylene ◽

Morphological Variables ◽

Length And Area ◽

Growing Conditions

Allocation of selenium (Se) in lettuce and its impact on root morphology were studied to better understand the growth responses of plants to added Se. Lettuce was grown in vermiculite under controlled growing conditions for seven weeks, and the allocation in the shoots and roots of selenate added in increasing dosages (0, 1, 10, 100, 500 and 1000 µg Se per 3.5-litre pot) as well as morphological variables of the roots were determined. The intermediate additions of 100 and 500 µg Se per pot seemed to produce the highest biomasses, although this was nearly masked by large scatter in the data. The Se contents both in roots and shoots increased roughly proportionally to the amount of Se added. However, at small additions Se was preferentially allocated to roots, whereas at larger additions the contents in roots and shoots (mg kg-1 dry matter) were roughly equal. Se treatments did not change the morphology of hypocotyls. On the contrary, the specific length and area of basal and lateral roots were smallest at intermediate Se additions, whereas the specific volume was largest at the largest Se addition. These effects of Se on root morphology were, however, not unambiguously related to plant growth. As the Se contents in roots increased, the roots grew thicker and the specific volume of lateral roots increased in agreement with a hypothesis of increased endogenous ethylene production.;

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FRUITFULL Is a Repressor of Apical Hook Opening in Arabidopsis thaliana

International Journal of Molecular Sciences ◽

10.3390/ijms21176438 ◽

2020 ◽

Vol 21 (17) ◽

pp. 6438

Author(s):

Miriam Führer ◽

Angelika Gaidora ◽

Peter Venhuizen ◽

Jedrzej Dobrogojski ◽

Chloé Béziat ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

In Silico ◽

Target Genes ◽

Growth Promotion ◽

In Silico Analysis ◽

Regulatory Elements ◽

Suitable Model ◽

Differential Growth ◽

Apical Hook ◽

Growth Transitions

Plants adjust their architecture to a constantly changing environment, requiring adaptation of differential growth. Despite their importance, molecular switches, which define growth transitions, are largely unknown. Apical hook development in dark grown Arabidopsis thaliana (A. thaliana) seedlings serves as a suitable model for differential growth transition in plants. Here, we show that the phytohormone auxin counteracts the light-induced growth transition during apical hook opening. We, subsequently, identified genes which are inversely regulated by light and auxin. We used in silico analysis of the regulatory elements in this set of genes and subsequently used natural variation in gene expression to uncover correlations between underlying transcription factors and the in silico predicted target genes. This approach uncovered that MADS box transcription factor AGAMOUS-LIKE 8 (AGL8)/FRUITFULL (FUL) modulates apical hook opening. Our data shows that transient FUL expression represses the expression of growth stimulating genes during early phases of apical hook development and therewith guards the transition to growth promotion for apical hook opening. Here, we propose a role for FUL in setting tissue identity, thereby regulating differential growth during apical hook development.

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Effects of Phosphate Shortage on Root Growth and Hormone Content of Barley Depend on Capacity of the Roots to Accumulate ABA

Plants ◽

10.3390/plants9121722 ◽

2020 ◽

Vol 9 (12) ◽

pp. 1722

Author(s):

Lidiya Vysotskaya ◽

Guzel Akhiyarova ◽

Arina Feoktistova ◽

Zarina Akhtyamova ◽

Alla Korobova ◽

...

Keyword(s):

Root Growth ◽

Lateral Roots ◽

Primary Root ◽

Growth Responses ◽

Root Tips ◽

P Deficiency ◽

Root Branching ◽

Auxin Concentration ◽

Shoot Mass ◽

Primary Root Length

Although changes in root architecture in response to the environment can optimize mineral and water nutrient uptake, mechanisms regulating these changes are not well-understood. We investigated whether P deprivation effects on root development are mediated by abscisic acid (ABA) and its interactions with other hormones. The ABA-deficient barley mutant Az34 and its wild-type (WT) were grown in P-deprived and P-replete conditions, and hormones were measured in whole roots and root tips. Although P deprivation decreased growth in shoot mass similarly in both genotypes, only the WT increased primary root length and number of lateral roots. The effect was accompanied by ABA accumulation in root tips, a response not seen in Az34. Increased ABA in P-deprived WT was accompanied by decreased concentrations of cytokinin, an inhibitor of root extension. Furthermore, P-deficiency in the WT increased auxin concentration in whole root systems in association with increased root branching. In the ABA-deficient mutant, P-starvation failed to stimulate root elongation or promote branching, and there was no decline in cytokinin and no increase in auxin. The results demonstrate ABA’s ability to mediate in root growth responses to P starvation in barley, an effect linked to its effects on cytokinin and auxin concentrations.

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