Genome-wide expression of low temperature response genes in Rosa hybrida L

Plants respond to low temperature stress during cold acclimation, a complex process involving changes in physiological and biochemical modifications. The rose serves as a good model to investigate low temperature responses in perennial ornamentals. In this study, a heterologous apple microarray is used to investigate genome-wide expression profiles in Rosa hybrida subjected to low temperature dark treatment. Transcriptome profiles are determined in floral buds at 0h, 2h, and 12h of low temperature treatment (4 °C). It is observed that a total of 134 transcripts are up-regulated and 169 transcripts are down-regulated in response to low temperature. Interestingly, a total of eight up-regulated genes, including those coding for two cytochrome P450 proteins, two ankyrin repeat family proteins, two metal ion binding proteins, and two zinc finger protein-related transcription factors, along with a single down-regulated gene, coding for a dynamin-like protein, are detected. Transcript profiles of 12 genes known to be involved in cold stress response are also validated using qRT-PCR. Furthermore, expression patterns of the AP2/ERF gene family of transcription factors are investigated in both floral buds and leaves. Overall, AP2/ERFs genes are more rapidly induced in leaves than in floral buds. Moreover, differential expression of several AP2/ERF genes are detected earlier in vegetative rather than in reproductive tissues. These findings highlight important roles of various low temperature response genes in mediating cold acclimation, thereby allowing roses to adapt to low temperatures, but without adversely affecting flower bud development and subsequent flowering, while vegetative tissues undergo early adaptation to low temperatures.

Proteomic Profiles Reveal the Function of Different Vegetative Tissues of Moringa oleifera

Moringa oleifera is a rich source of bioactive compounds and is widely used in traditional medicine and food for its nutritional value; however, the protein and peptide components of different tissues are rarely discussed. Here, we describe the first investigation of M. oleifera proteomes using mass spectrometry and bioinformatics methods. We aimed to elucidate the protein profiles of M. oleifera leaves, stem, bark, and root. Totally 202 proteins were identified from four vegetative organs. We identified 101 proteins from leaves, 51 from stem, 94 from bark and 67 from root, finding that only five proteins existed in both four vegetative parts. The calculated pI of most of the proteins is distributed in 5-10 and the molecular weight distributed below 100 kDa. Functional classification analysis revealed that proteins which are involved in catalytic activities are the most abundant both in leaves, stem, bark and root. Identification of several heat shock proteins in four vegetative tissues might be adaptive for resistance to high temperature environmental stresses of tropical or subtropical areas. Some enzymes involved in antioxidant processes were also identified in M. oleifera leaves, stem, bark and root. Among the four tissues studies here, leaves protein content and molecular diversity were the highest. The identification of the flocculating protein MO2.1 and MO2.2 in the bark and root provides clue to clarify the antimicrobial molecular mechanisms of root and bark. This study provides information on the protein compositions of M. oleifera vegetative tissues that will be beneficial for potential drug and food supplement development and plant physiology research.

Characterization of 5'UTR of rice ClpB-C/Hsp100 gene: evidence of its involvement in post-transcriptional regulation

Rice (Oryza sativa) ClpB-C (OsClpB-C) protein is expressed upon heat stress in vegetative tissues and constitutively in seeds. We produced stably transformed Arabidopsis plants carrying β-glucuronidase (Gus) reporter gene downstream to 1-kb OsClpB-C promoter (1kbPro plants). In the 1kbPro plants, expression of Gus transcript and protein followed the expression pattern of OsClpB-C gene in rice plants, i.e., heat induced in vegetative tissues and constitutive in seeds. Next, we produced transgenic Arabidopsis plants containing Gus downstream to 862-bp fragment of OsClpB-C promoter [lacking 138 nucleotides from 3' end of the 5'untranslated region (5'UTR); ∆UTR plants). In ∆UTR plants, Gus transcript was expressed in heat-inducible manner, but strikingly, Gus protein levels were negligible after heat treatment. However, Gus protein was expressed in ∆UTR seedlings at levels comparable to 1kbPro seedlings when recovery treatment of 22 °C/2 h was given post heat stress (38 °C/15 min). This suggests that 5'UTR of OsClpB-C gene is involved in its post-transcriptional regulation and is an obligate requirement for protein expression during persistent heat stress. Furthermore, the Gus transcript levels were higher in the polysomal RNA fraction in heat-stressed seedlings of 1kbPro plants as compared to ∆UTR plants, indicating that 5'UTR aids in assembly of ribosomes onto the Gus transcript during heat stress. Unlike the case of seedlings, Gus protein was formed constitutively in ∆UTR seeds at levels comparable to 1kbPro seeds. Hence, the function of 5'UTR of OsClpB-C is dispensable for expression in seeds.

Pretreated cheese whey wastewater management by agricultural reuse: chemical characterization and response of tomato plants Lycopersicon esculentum Mill. under salinity conditions

The agricultural reuse of pretreated industrial wastewater resulting from cheese manufacture is shown as a suitable option for its disposal and management. This alternative presents attractive advantages from the economic and pollution control viewpoints. Pretreated cheese whey wastewater (CWW) has high contents of biodegradable organic matter, salinity and nutrients, which are essential development factors for plants with moderate to elevated salinity tolerance. Five different pretreated CWW treatments (1.75 to 10.02 dS m(-1)) have been applied in the tomato plant growth. Fresh water was used as a control run (average salinity level=1.44 dS m(-1)). Chemical characterization and indicator ratios of the leaves, stems and roots were monitored. The sodium and potassium leaf concentrations increased linearly with the salinity level in both cultivars, Roma and Rio Grande. Similar results were found in the stem sodium content. However, the toxic sodium accumulations in the cv. Roma exceeded the values obtained in the cv. Rio Grande. In this last situation, K and Ca uptake, absorption, transport and accumulation capacities were presented as tolerance mechanisms for the osmotic potential regulation of the tissues and for the ion neutralization. Consequently, Na/Ca and Na/K ratios presented lower values in the cv. Rio Grande. Na/Ca ratio increased linearly with the salinity level in leaves and stems, regardless of the cultivar. Regarding the Na/K ratio, the values demonstrated competition phenomena between the ions for the cv. Rio Grande. Despite the high chloride content of the CWW, no significant differences were observed for this nutrient in the leaves and stems. Thus, no nitrogen deficiency was demonstrated by the interaction NO3(-)/Cl(-). Nitrogen also contributes to maintain the water potential difference between the tissues and the soil. Na, P, Cl and N radicular concentrations were maximized for high salinity levels (≥2.22 dS m(-1)) of the pretreated CWW.