Influence of the fungicide TMTD as a stress factor on the ultrastructure of pea (Pisum sativum L.) symbiotic nodules

The negative effects of tetramethylthiuram disulfide (TMTD) on the ultrastructural organization of nodules of pea wild-type line SGE were studied.

Overexpression of TaBADH increases salt tolerance in Arabidopsis

Soil salinization is an important threat to wheat growth and production. Previous transcriptome analysis showed that the expression of the betaine aldehyde dehydrogenase (BADH) gene differed significantly between cultivars with strong or weak salinity tolerance. Herein, the BADH gene from the wheat cultivar Dongnongdongmai 1 was cloned and transformed into wild-type Arabidopsis to identify its function in salt tolerance. Root length was calculated at 0, 50, 100, 150, and 200 mmol L−1 NaCl for 7 d. The relative electrolytic leakage (REL), GB content, and BADH activity were measured at 150 mmol L−1 NaCl for 1 and 3 d. It was determined that BADH activity and the GB content of TaBADH-overexpressed transgenic (TaBADHOE) lines were significantly higher than in wild-type lines. Salt stress analysis showed that the root length of TaBADHOE lines 4, 18, and 19 were 0.44, 0.54, and 0.35 cm, respectively, which were significantly longer than the 0.24 cm roots of the wild-type line in the media containing 150 mmol L−1 NaCl for 7 d. In addition, the RELs of transgenic lines 4, 18, and 19 were 0.37, 0.33, and 0.42, respectively, which is significantly lower than the 0.63 of the wild-type line in media containing 150 mmol L−1 NaCl for 3 d. These results demonstrate that TaBADH significantly increased plant salt tolerance, indicating that genetic transformation of TaBADH may be an effective and sustainable breeding method for increasing salt tolerance in wheat cultivars.

PGPR-Induced Growth Stimulation and Nutrient Acquisition in Maize: Do Root Hairs Matter?

Here we describe the effects of the well-characterized, commercial plant growth-promoting rhizobacteria (PGPR) strain Pseudomonas sp. DSMZ 13134 (Proradix®) on plant growth, root morphology, and nutrient acquisition of a maize mutant (rth2) with impaired root hair production as compared with the corresponding wild type line, to study the importance of root hairs for the interaction of the PGPR strain with the host plant. The study was conducted in rhizobox culture with a sand–soil mixture and moderate P supply. Root hair development of the mutant was clearly impaired, reflected by slower growth and limited elongation as compared with the wild type line. This defect was compensated by more intense root growth and fine root production of the mutant which was particularly expressed after inoculation with Proradix®. By contrast, PGPR inoculation had no effect on root hair length. The beneficial effects of Proradix® on root growth were reflected in higher shoot contents of the macronutrients P and K. Interestingly, negative effects on shoot accumulation of the micronutrients Zn and Cu were observed. These findings support proposed PGPR effects of this strain but also show limitations that may be explained by additional strain-specific properties. Possible implications of these findings are discussed.

Characteristics of Thermoluminescence Bands of Euglena Cells Belonging to 2 Lines Presenting Different Degrees of Diuron-Resistance

We have analysed the thermoluminescence (TL) properties of two lines of Euglena exhibiting two degrees of resistance to diuron, by a factor of 100 (ZR 25) and 1000 (ZR 250) respectively, as compared to wild type line (Z). In addition, the two ZR lines developped an identical resistance to atrazine since the I50 for this herbicide in each line was 75 times larger than in wild type. Special TL characteristics were evidenced in the two lines. Bands after 2 flashes (or more) showed a shift of the peak maximum towards low temperature, the shift being the largest in the most DCMU-resistant cells. Similar results were obtained with isolated thylakoids, except that the TL bands appeared at a temperature higher than in corresponding cells. Oscillations in the amplitude of the bands in a flash sequence were largely damped in cells (and thylakoids), particularly in the most DCMU-resistant lines. The results are interpreted as indicating accumulation of Qᴀ −Qʙ after flashes due to a decrease of the equilibrium constant for the reaction Qᴀ − Qʙ ⇄ QᴀQʙ− accompanying the DCMU resistance.