Effect of different light on wheat (Triticum aestivum L) growth and role of phytochrome

Among the various naturally occurring abiotic factors regulating plant development, different types of light play an important role in them. Photosynthesis, photoperiodism, and photo morphogenesis. In this trial the effects of different colors of light on (seed) germination, phytochrome conversion, length of seedling, biomass production in wheat varieties Shalkot and Tandojam. The rate of germination data indicates white 96%, Red 100%, far-red 95%, Blue 95%, and dark 64%, in Shalkot. In Tandojam rate of germination 94% White, 93% red, 82% far red, 92% blue, and 50% dark, were observed. Root and shoot length were higher in Shalkot under white light. Difference between dry and fresh weight in Shalkot under white, red, far-red, blue, dark, 1.66g, 0.94g, 0.98g, 0.97g, 0.6g, respectively. In Tandojam difference between dry and fresh weight observed under white, red, far-red, blue, dark, 1.48g, 0.92g, 0.70g, 0.97g, 0.4g respectively. By using bioinformatics tools identified some light-harvesting genes in wheat (Triticum aestivum) by using model plant Arabidopsis thaliana. The identified light-harvesting genes include cl02879, cl25816, cl33336, cl31857, cl28913.


Introduction
Light plays several important roles in the life of several microorganisms, animals, and plants. The behaviour of plant metabolism in response to different biotic and abiotic factors which cause damage, such as UV radiation, unfavourable temperature, drought, salinity, is regulated by a system of phytochrome [1][2][3]. In light the plant photoreceptor playing a major role, Photoreceptor contains a phytochrome [4][5]. A large range of physiological developments from the germination of the seed to flowering and the fruiting is controlled by the system of phytochrome [6][7][8]. Plants go through from two different programs of development: photo morphogenesis in the existence of light and skotomorphogenesis in the in-existence of light. The plant that is grown in dark showed phenotype etiolated such as apical hooks, long hypocotyls, and cotyledons are yellow and closed. In comparison, the plant which is grown in light exhibits phenotype of photo morphogenesis distinguished by green open and enlarge cotyledons, and small hypocotyls. Light also regulates other developmental and growth program by managing shade avoidance, the flowering of photoperiodic and directional growth [9].
On the display of red light phytochrome completely change forms from inactive phytochrome red (660nm) to active phytochrome far-red (730nm) [9]. Red light absorption by phytochrome red transforms the protein to the phytochrome far-red that is far-red absorbing form. Far-red light absorption by phytochrome far-red turns the confirmation again to phytochrome red. Therefore to the first estimation, phytochrome maybe regards as convertible light-activated red/far-red switches of molecular [9][10]. Far-red and red light has a great impact on the growth extension, it is mean that it affects the stem length, plant height, and also the left size [11], [12,13]. Blue light participates in a large number of processes of the plant such as the opening of stomata, phototropism, the photosynthetic function of the leaf, and photo morphogenesis [14,15].
Wheat is a widely grown crop around the world for its high nutritive value [16]. The demand for wheat is more in comparison to other crops. Wheat is mostly cultivated in temperate areas [17]. The effect of light quality on the growth and morphology of wheat has been studied [18,19]. In the present study, we used the different light type that regulates the phytochrome, developmental rate of wheat with valuable information about light-harvesting candidate genes which work in light stress.

Materials and Methods
Two wheat verities (Shalkot, Tandojam) seeds were collected from the seed certification department Islamabad, Pakistan. Selected seeds were sterilized by Hydrogen peroxide (10%) for five minutes, then washed three times with distilled water and air dry for 30 minutes [20]. Seeds were imbibed in 100 ml distilled water for 12 hours. For the germination test, the 10 viable seeds were placed on a double layer of Whatman filter paper in a 9cm diameter petri dish. Initial protuberances in the wheat seeds were showed the germination of the seed [21]. Different light (white, red, far-red, blue, dark conditions) were used for the germination of sterilized seeds [22].

Dark and white light condition
For dark treatment, the sterilized seeds petri dishes were cover with aluminum foil and placed into the cotton box (provide the darkness). For white light treatment, the petri dishes were kept in the germinator under the white light fluorescent (Philips TLD18W/54-764). Allow them to germinate for seven days [23].

Red, far-red and blue light condition
For red and blue light Plexiglas filter (3mm thick) was used. While for far-red light arranged a red filter between two blue Plexiglas filters. And passed tube light (Philips TLD18W/54-765) in Plexiglas filters [24].

Gene collection
The gene that expressed during light stress condition were taken from the model plant Arabidopsis thaliana by using NCBI database, to identify the light-harvesting gene in wheat (Triticum aestivium) [25]. In model plant identification of computational gene aid in gene annotation by using Nr, to develop the relation between wheat (Triticum aestivium) and Arabidopsis thaliana.

Blast
A similarity sequence was obtained by using the blast. The coding region of the sequence of the nucleotide of Arabidopsis thaliana was submitted to BLAST, that organism we selected that have maximum query cover and identity [26].

Open reading frame
FASTA sequence of wheat (Triticum aestivium) and Arabidopsis thaliana were submitted to ORF-finder. Which gives the coding sequence of the nucleotide of the model plant and reference plant.

Conserve domain
By using the data of gene in conserve domain we found wheat (Triticum aestivium) and Arabidopsis thaliana families' information these families were present in both model plant and reference plant [27].

Statistical analysis
The data were analyzed with analysis of variance (ANOVA) using the statistical package Genstat 9.2 (VSN International Ltd., Hemel Hempstead, Hertfordshire, UK). The mean values were compared and separated based on Fisher's least significant difference (LSD) test.

Seed germination of wheat varieties under various light conditions at the optimal temperature (20ºC)
Two varieties of wheat Shalkot and Tandojam were observing under various light conditions (white light, red light, far-red light, blue light, and dark). The germination was started from 1 st day in all light conditions. In shallots maximum germination observed under red light (100%), as compared to white light (96.66%), Far-red light (95.71%), and Blue light (95.23%) the minimum germination rate were observed in dark condition (64.29%) ( Table 1).
Values are means of three replicates ± SE and values bearing different letters in the same column are no-significantly different from each other Table 1. The percentage of seeds germination of Shalkot and Tandojam under different light conditions.

Treatments
White

Comparative study of wheat with Arabidopsis thaliana
Identify the light-harvesting genes of reference plant wheat (Triticum aestivium) and five genes of sample plant Arabidopsis thaliana from NCBI (National center for biotechnology information) databases, such as ORF (open frame readings), BLAST (basic local alignment search tool), and conserve domain were used to identify the gene ID, accession number and query cover. Through ORF finder entire open reading frame of a selected sequence is determined. The basic local alignment search tool (BLAST) was used to disclose the query cover of reference plant wheat (Triticum aestivum) and model plant Arabidopsis thaliana. Selected 5 genes that had maximum query cover (99%, 99%, 75%, 72%, and 62%). NCBI tool conserves domain database was used to reveal the gene families. The superfamily was present in both plants Arabidopsis thaliana and wheat (Triticum aestivum), like Chloroa_b-bind, KAR9, ftsH, PLN02281, and SIMIBI (Table. 3). Table 3. Comparative study of Triticum asestivium with Arabidopsis thaliana.

Discussion
Interactions among stress action and plant growth are intricate as plant corresponds with, many environmental factors. As the most significant widely distributed stress of the environment, light is bestknown to have an important impact on wheat. In our study white light and red were showed maximum results with an aspect of germination percentage, length of seedling, and biomass. A similar result was observed [28]. The ecological important attributed to the response of light in these families is that the light serves as an indicator of soil depth, permitting higher germination of seed on the surface than seeds bury in soil [29][30]. Plants have considerably extensive signaling mechanisms of light, with photoreceptors consecrate to various wavelengths in the spectrum of light and interactions among these photoreceptors and their pathways of signal transduction. Availability of light on the growth of root gonna be the basic effect of availability of differential sugar to roots this is because, in shoot presence of photosynthesis, there is significant proof for more complex signaling effects of various light environments aspects [31].
The light receptor group performs blue light deduction. They act immoderately in promoting elongation of the primary root, the opening of stomata in Arabidopsis, and induction of flowering circadian clock [32]. A similar result was observed in the case of root elongation in our study.
In the case of a far-red light study, our result was showed the positive aspects. Through Phytochromes, the Signaling of r/fr light was used by plants that regulate shade avoidance, germination, and senescence [33. The red light absorbed by inactive phytochrome red that result in photoconversion into a form of active phytochrome far-red then to inactivate it absorbs far-red light. To detect light connected phytochromobilin is utilized by phytochrome and light signal is transferred which goes through from convertible conformation variations [34,35].
By using the bioinformatics tool harvesting genes were expressed under different light stress. Our results based on five harvesting genes of wheat compared with the model plants Arabidopsis. It has been shown that they may also be involved in response to different light conditions. Wheat can react to under the active metabolism of various phytohormones, e.g., SA, ABA, and JA that are proposed to be intricate in acclimation of light [36].

Conclusion
In conclusion, it is clear that different types of lights such as (redfar red, blue, white and dark) regulates the various physiological, anatomy and cell signaling pathways. Different light effects on seed germination and plant growth. Phytorome is most important protein which directly affect by reversible form of red to far-red light .Under light stress (different light intensity and quality of light) expresses different genes. There are still many query are unclear at molecular level. Especially cell signaling and gene. But Bioinformatics study play promoting role regarding light stress gene family members which are active under different type of light stress.

S.No
Gene