Citrulline Is an Important Biochemical Indicator in Tolerance to Saline and Drought Stresses in Melon

Abstract

Salt- and drought-induced alterations in citrulline were assessed in 4 local melon genotypes, 2 sensitive (CU-52, CU-94) and 2 tolerant (CU-196, CU-280), grown in vermiculite in a growth chamber. Salt and drought stresses were started using 30-day-old plants, with 250 mM NaCI and 45 mM PEG (−1.0 MPa) and continued for 12 days. After 12 days under salt and drought conditions, the citrulline contents were increased in the tolerant CU 196 to 25.10 μmol gDW−1 and 24.10 μmol gDW−1 for salt and drought stresses, respectively. However, the citrulline contents of the sensitive CU-52 were 11.68 μmol gDW−1 and 11.76 μmol gDW−1 for salt and drought, respectively. The striking alteration was obtained in the citrulline accumulation. The tolerant melons accumulated 2 times more citrulline than the sensitive melons. For assessing or screening melon genotypes in a large number of accessions or breeding lines for their tolerance to salinity and drought during their young plant stage, the amount of citrulline accumulation in response to the given treatments might be considered as a novel biochemical indicator of interest in early selection studies.

Transcriptome analyses reveal genotype- and developmental stage-specific molecular responses to drought and salinity stresses in chickpea

“…The production of these osmolytes under abiotic stresses is considered as an adaptive feature 41 . Recently, citrulline has been established as an important biochemical indicator of drought and salinity tolerance 42 . Trehalose is a non-reducing disaccharide present in very low quantity in the plants.…”

Heritability and Genetic Variance Components Associated with Citrulline, Arginine, and Lycopene Content in Diverse Watermelon Cultigens

“…Historically, watermelon cultivars have not been bred for high lycopene or citrulline concentrations. Breeding for increased citrulline and lycopene could increase the marketability of watermelon as a health food, while contributing to improved plant stress tolerance (Akashi et al, 2001;Kusvuran et al, 2013;Wang et al, 2014).…”

“…In related Citrullus species, studies have shown that citrulline content increases in the foliage during drought stress and may improve plant tolerance to stress (Akashi et al, 2001;Wang et al, 2014). Similarly in melon, foliage citrulline content is an important indicator for drought stress (Kusvuran et al, 2013). In developing watermelon fruit, citrulline content is low, reaching peak levels just before maturity, and declining as fruit ages (Fish, 2014).…”

Citrulline and Arginine Content of Taxa of Cucurbitaceae

“…Additionally, mouse melon, horned melon, and bitter gourd (arils) may be interesting sources of arginine-family amino acids, perhaps because of their large seed and aril content relative to mesocarp.Horticulturae 2019, 5, 22 2 of 11 and potential use as a biomarker for selecting tolerant cultigens [14][15][16][17]. Several genes are upregulated in watermelon during drought stress (including glutamine acyl transferases), and others downregulated, further supporting these ideas [18][19][20]. In drought-stressed cucumbers, citrulline, and proline metabolism were down-regulated upon alleviation of the stress involving CO 2 levels; citrulline was identified using ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF MS) [21].Citrulline content in domestic watermelon fruit varies with cultivar, ploidy, genotype, flesh color, and fruit anatomy.…”