Sound waves delay tomato fruit ripening by negatively regulating ethylene biosynthesis and signaling genes

AbstractRegulation of tomato fruit ripening may help extend fruit shelf life and prevent losses due to spoilage. Here, tomato fruit were investigated whether sound treatment could delay their ripening. Harvested fruit were treated with low-frequency sound waves (1kHz) for 6h, and then monitored various characteristics of the fruit over 14-days at 23±1°C. Seven days after the treatment, 85% of the treated fruit were green, versus fewer than 50% of the non-treated fruit. Most of the tomato fruit had transitioned to the red ripening stage by 14 days after treatment. Ethylene production and respiration rate were lower in the sound-treated than non-treated tomatoes. Furthermore, changes in surface color and flesh firmness were delayed in the treated fruit. To investigate how sound wave treatment effects on fruit ripening, the expression of ethylene-related genes was analyzed by quantitative real-time RT-PCR analysis. The expression level of several ethylene biosynthetic (ACS2, ACS4, ACO1, E4 and E8) and ripening-regulated (RIN, TAGL1, HB-1, NOR, CNR) genes was influenced by sound wave treatment. These results indicated that sound wave treatment delays tomato fruit ripening by altering the expression of important genes in the ethylene biosynthesis and ethylene signaling pathways

Phenotyping of rice in salt stress environment using high-throughput infrared imaging

Phenotyping of rice (Oryza sativa L. cv. Donggin) in salt stress environment using infrared imaging was conducted. Results were correlated with the most frequently used physiological parameters such as stomatal conductance, relative water content and photosynthetic parameters. It was observed that stomatal conductance (R2 = –0.618) and relative water content (R2 = –0.852) were significantly negatively correlated with average plant temperature (thermal images), while dark-adapted quantum yield (Fv/Fm, R2 = –0.325) and performance index (R2 = –0.315) were not consistent with plant temperature. Advantages of infrared thermography and utilization of this technology for the selection of stress tolerance physiotypes are discussed in detail

Identification of Rice Accessions Associated with K+/Na+ Ratio and Salt Tolerance Based on Physiological and Molecular Responses

The key for rice plant survival under NaCl salt stress is maintaining a high K+/Na+ ratio in its cells. Selection for salt tolerance rice genotypes based on phenotypic performance alone will delay in progress in breeding. Use of molecular markers in tandem with physiological studies will help in better identification of salt tolerant rice accessions. Eight rice accessions along with the check Dongjin were screened using 1/2 Yoshida solution with 50 mmol/L NaCl at the seedling stage. The accessions IT001158, IT246674, IT260533 and IT291341 were classified as salt tolerant based on their K+/Na+ ratios. Seventeen SSR markers reported to be associated with K+/Na+ ratio were used to screen the accessions. Five SSR markers (RM8053, RM345, RM318, RM253 and RM7075) could differentiate accessions classified based on their K+/Na+ ratios. Banding pattern of the accessions was scored compared to the banding pattern of Dongjin. The study differentiated accessions based on their association of K+/Na+ ratio with molecular markers which are very reliable. These markers can play a significant role in screening large set of rice germplasms for salt tolerance and also help in identification of high-yielding varieties with better salt tolerance. The salt tolerant accessions can be taken forward into developing better varieties by conventional breeding and exploring genes for salt tolerance

Salt Tolerance in Rice: Focus on Mechanisms and Approaches

Salt tolerance is an important constrain for rice, which is generally categorized as a typical glycophyte. Soil salinity is one of the major constraints affecting rice production worldwide, especially in the coastal areas. Susceptibility or tolerance of rice plants to high salinity is a coordinated action of multiple stress responsive genes, which also interacts with other components of stress signal transduction pathways. Salt tolerant varieties can be produced by marker-assisted selection or genetic engineering by introducing salt-tolerance genes. In this review, we have updated on mechanisms and genes which can help in transferring of the salt tolerance into high-yielding rice varieties. We have focused on the need for integrating phenotyping, genomics, metabolic profiling and phenomics into transgenic and breeding approaches to develop high-yielding as well as salt tolerant rice varieties

A Dominant Negative OsKAT2 Mutant Delays Light-Induced Stomatal Opening and Improves Drought Tolerance without Yield Penalty in Rice

Stomata are the main gateways for water and air transport between leaves and the environment. Inward-rectifying potassium channels regulate photo-induced stomatal opening. Rice contains three inward rectifying shaker-like potassium channel proteins, OsKAT1, OsKAT2, and OsKAT3. Among these, only OsKAT2 is specifically expressed in guard cells. Here, we investigated the functions of OsKAT2 in stomatal regulation using three dominant negative mutant proteins, OsKAT2(T235R), OsKAT2(T285A) and OsKAT2(T285D), which are altered in amino acids in the channel pore and at a phosphorylation site. Yeast complementation and patch clamp assays showed that all three mutant proteins lost channel activity. However, among plants overexpressing these mutant proteins, only plants overexpressing OsKAT2(T235R) showed significantly less water loss than the control. Moreover, overexpression of this mutant protein led to delayed photo-induced stomatal opening and increased drought tolerance. Our results indicate that OsKAT2 is an inward- rectifying shaker-like potassium channel that mainly functions in stomatal opening. Interestingly, overexpression of OsKAT2(T235R) did not cause serious defects in growth or yield in rice, suggesting that OsKAT2 is a potential target for engineering plants with improved drought tolerance without yield penalty

New Parameters for Seedling Vigor Developed via Phenomics

Early seedling establishment in rice (Oryza sativa L.), which is measured by primary/secondary tiller, shoot length, biomass, root-related traits, and leaf area index, is an important trait because it helps to compete for light, air, and water for better tolerating various abiotic stresses. Consequently, it can affect the yield. However, there are not many research studies on this subject. Furthermore, previous studies have only measured the target traits once. However, this does not reflect the variation of growth rate during the seedling stage. Thus, two data points, two weeks and four weeks after planting, were used in the current study. As a result, two QTL regions were detected for the growth differences via plant height and green area (reflecting tillering). We expect that these results can be utilized by breeders to evaluate and select vigorous seedlings for their breeding programs