Phytonutrients and Metabolism Changes in Topped Radish Root and Its Detached Leaves during 1 °C Cold Postharvest Storage

Glucosinolates, lipid-soluble vitamins E and K contents, primary metabolites and plant hormones were analyzed from topped radish root and detached leaf during storage at 1 °C. The topped root was analyzed at 0, 5, 15, 30, and 90 days after storage while the detached leaf was analyzed at 0, 5, 15, 30, and 45 days in an airtight storage atmosphere environment. The results showed that aliphatic glucosinolates were gradually decreased in leaf but not in root. There was a highly significant correlation between tryptophan and 4-methoxyindoleglucobrassicin in both tissues (r = 0.922, n = 10). There was no significant difference in vitamins E and K in leaf and root during storage. Plant hormones partially explained the significantly changed metabolites by tissue and time, which were identified during cold storage. Phenylalanine, lysine, tryptophan, and myo-inositol were the most important biomarkers that explained the difference in leaf and root tissue during cold storage. The most different metabolism between leaf and root tissue was starch and sucrose metabolism. Therefore, different postharvest technology or regimes should be applied to these tissues.

Root tissue strength and storage losses of sugar beet varieties as affected by N application and irrigation

There is some evidence that sugar beet root tissue strength affects damage susceptibility and storage losses. This study aimed at analyzing the effect of N application and of irrigation on tissue strength of sugar beet varieties, on root composition, and on root tip breakage and storage losses. For this purpose, field trials in six replicates with three sugar beet varieties were carried out with three N doses in The Netherlands and Belgium in 2018 and 2019, alternatively with three irrigation treatments in Sweden in 2018 and 2019. Results show a low impact of N application and irrigation on puncture resistance, tissue firmness and compressive strength of the roots, while varieties differed always stronger and significantly. Cell wall composition (pectin, hemicellulose, cellulose, lignin) did not differ markedly in roots from different environments (sites, years) and varieties, giving no explanation for differences in tissue strength. However, the percentage of cell wall material (AIR, marc) and of dry matter were higher in roots with higher tissue strength. Root tip breakage and sugar losses during storage tended to be lower when root compressive strength of varieties was higher. Hence, root tissue strength could serve as an indirect selection criterion for reduced damage susceptibility and improved storability of sugar beet varieties.

Discrepancies in Serology-Based and Nucleic Acid-Based Detection and Quantitation of Tomato Spotted Wilt Orthotospovirus in Leaf and Root Tissues from Symptomatic and Asymptomatic Peanut Plants

Thrips-transmitted tomato spotted wilt orthotospovirus (TSWV) causes spotted wilt disease in peanuts. A serological test (DAS-ELISA) is often used to detect TSWV in peanut leaf samples. However, in a few studies, DAS-ELISA detected more TSWV infection in root than leaf samples. It was not clear if the increased detection was due to increased TSWV accumulation in root tissue or merely an overestimation. Additionally, it was unclear if TSWV detection in asymptomatic plants would be affected by the detection technique. TSWV infection in leaf and root tissue from symptomatic and asymptomatic plants was compared via DAS-ELISA, RT-PCR, and RT-qPCR. TSWV incidence did not vary by DAS-ELISA, RT-PCR, and RT-qPCR in leaf and root samples of symptomatic plants or in leaf samples of asymptomatic plants. In contrast, significantly more TSWV infection and virus load were detected in root samples of asymptomatic plants via DAS-ELISA than other techniques suggesting that DAS-ELISA overestimated TSWV incidence and load. TSWV loads from symptomatic plants via RT-qPCR were higher in leaf than root samples, while TSWV loads in leaf and root samples from asymptomatic plants were not different but were lower than those in symptomatic plants. These findings suggested that peanut tissue type and detection technique could affect accurate TSWV detection and/or quantitation.

Identification of endophytic and rhizosphere bacteria in rice (Oryza sativa L.) in the experimental field at Payakumbuh State Agriculture Polytechnic, West Sumatra, Indonesia

The decrease of soil fertility and fewer soil microorganisms will lower crop production, particularly rice, thus threatening the national food security program. This study is (a) to isolate and identify the bacteria in the endophytic and rhizosphere of rice plants (b) to study the bacteria from the endophytic and rhizosphere of rice plants which potentially stimulate plant growth. The experiment was carried out at the Laboratory of Food Crop Cultivation at Payakumbuh State Agriculture Polytechnic, Limapuluh Kota Regency, West Sumatra for four months. The sampling method was carried out by random sampling at rice planting in the Payakumbuh State Agriculture Polytechnic Experimental Field. Endophytic bacteria were taken from the root tissue of rice plants, and rhizosphere bacteria were taken from a layer of soil around rice roots. Isolation of bacteria was carried out by using the pour plate and scratchplate methods. Four bacteria were identified using the 16S rRNA sequencing method. The identification results showed that in the rice root tissue found the bacteria Chromobacterium rhizoryzae and Brevibacillus brevis. In the rice rhizosphere, Bacillus pseudomycoides and Bacillus thuringiensis are found. Bacteria are dominated by the Bacillus genera which can stimulate plant growth.

Genome Sequence of the Agrobacterium salinitolerans DG3-1 Isolated from Cotton Roots

Agrobacterium salinitolerans DG3-1 is an endophytic bacterium isolated from cotton root tissue. Our previous work has shown that it can inhibit the growth of Fusarium and Verticillium wilt pathogens as well as increase the chlorophyll content of cotton leaves. Here, we reported the complete genome sequence of strain DG3-1, which was analyzed by sequence reads generated from Nanopore PromethION and Illumina NovaSeq PE150 platforms. This genome sequence could be used to clarify the possible mechanism of DG3-1 at the gene level.

Root Structure and Function of Grapevine Rootstocks (Vitis) in Response io Salinity

Purpose Accessing freshwater resources becomes more complex in arid and semi-arid areas due to increased demands and declining water quality. Alternative water sources for agriculture such as saline and recycled water are currently being used. A better understanding of roots' response to irrigation with saline water is crucial for future agriculture in arid and semi-arid areas. Methods Three grapevine (Vitis) rootstocks were examined, and their roots' responses to salinity were studied. The rootstocks were planted in pots filled with sand and were grown in a commercial net house subjected to two salinity treatments: 10 mM and 30 mM NaCl (EC = 2 and 4 ds m-1, respectively). We measured root morphologic and anatomic properties at the end of the experiment. Results The specific root area increased in response to salinity due to reduced root tissue density. In addition, a reduction in the average root diameter also affected the specific root area by increasing the surface area to volume ratio. Plant biomass was allocated primarily to the shoot in all three rootstocks, reducing the root to shoot ratio. At the same time, the bottom part of the root zone was more affected by salinity. SO4 showed improved chloride and sodium exclusion, concomitant with a significant increase in its narrow roots' contribution to the surface area. Conclusion Narrow roots play a more prominent role in the acquisition of water and nutrients as salinity increases. Furthermore, a decrease in root tissue density and average diameter may contribute to salt exclusion from the roots.

The Role of Root Tissue Membrane Proteins in Replanting Stress in Rehmannia glutinosa

The perennial herbaceous plant, Rehmannia glutinosa Libosch, is one of traditional Chinese medicines with a long history of cultivation and medicinal use. However, in production of R. glutinosa, replanting disease severely affected its yield and medicinal quality. Replanting disease is the special stress including biotic and abiotic factors. The membrane proteins system plays the important role in process of plants responding to stress factors. In this study, the differentially expressed root tissue membrane proteins between first planted and replanted R. glutinosa were identified through the isobaric tag for relative and absolute quantitation (iTRAQ). As a result, the membrane protein extraction kit could highly effectively extract the membrane proteins from R. glutinosa root tissue. A total of 698 differential membrane proteins between first planted and replanted R. glutinosa were obtained. Functional analysis revealed that the differential membrane proteins were involved in various metabolic pathways, including transport and breakdown, signal transduction, membrane trafficking and environmental response. Two important molecular events that occurred in cellular membrane of replanted R. glutinosa including the imbalance of ROS (Reactive Oxygen Species) metabolism and immune response were identified in this study. When replanted R. glutinosa plants faced the complex environment factors in rhizosphere, the proteins located in cellular membrane were often first activated to response to stress stimulus, resulted in the upregulated expression of a large number of LRR-RLKs (Leucine-rich repeat receptor-like kinases) receptor proteins. Meanwhile, the Ca2+ signal proteins and related receptor proteins transmitted and responded to the replanting stress, which induced severe oxidative stress response in the cell membrane of R. glutinosa, membrane peroxidation, intracellular signal disorder, and eventually produce replanting disease. Our findings provided the theoretical and data foundation for elucidating the key mechanisms associated with replanting stress. © 2021 Friends Science Publishers

Metabolic And Biochemical Changes Associated With Root Growth Restriction Under Cd Stress During Maize Pre-Emergence

Cadmium (Cd) pollution of agricultural soils is a growing global problem. Plant growth restriction is the main visible symptom of Cd toxicity, and this metal may be particularly harmful to the preformed, seminal root during the pre-emergence stage. In the present study, we focused on Cd phytotoxicity on seminal root growth, nutrient composition, redox status, and hormone homeostasis during the pre-emergence stage, distinguishing between the root apex and the remaining root tissue. After 72 h of metal exposure (50 and 100 µM CdCl2), root length and biomass was diminished, as well as Ca, Fe, Mg, and Mn contents. A redox imbalance was evidenced by changes in peroxidase activities and decreased ascorbate-dehydroascorbate ratio in both root parts. There was less accumulation of carbonylated proteins in both root fractions upon exposition to 50 µM Cd, compared to 100 µM Cd, and this was related to increased 20S proteasome activities. Cd incremented ABA, IAA, and SA contents, but drastically reduced the biologically active gibberellin GA4 and the conjugate jasmonoyl isoleucine (JA-Ile). We demonstrated that the whole root tissue is involved in maize response to Cd stress, which entails redox and hormonal rearrangements, probably directed to widen plant defense lines at the expense of root growth.