Seed priming with cold plasma improved seedling performance, secondary metabolism, and expression of deacetylvindoline O‐acetyltransferase gene in Catharanthus roseus

Abstract

The plasma-primed seeds of Catharanthus roseus were cultured in a hormone-free culture medium under sterile conditions. Plasma of 30 or 60 s improved root length (mean = 41.4%) and biomass (mean = 47%), whereas plasma of 90 s delayed plant growth. The plasma treatments enhanced concentrations of photosynthetic pigments and soluble phenols. Plasma of 90 s increased the proline level. With a similar trend, plasma priming induced activities of phenylalanine ammonia-lyase, catalase (about twofold) and peroxidase (31%) enzymes. Plasma also upregulated the expressions of deacetylvindoline O-acetyltransferase gene by an average of 7.8 times. Similarly, the plasma-treated seedlings contained higher concentrations of alkaloids (mean = 72%). Here, molecular evidence is provided on the plasma-associated modifications in secondary metabolism. K E Y W O R D S applied physics, Catharanthus roseus, cold plasma, gene expression, secondary metabolism, seed priming 1

Mechanisms of Plasma-Seed Treatments as a Potential Seed Processing Technology

“…Regarding secondary metabolism, an increase in enzymatic antioxidants like catalase [58], superoxide dismutase [78], phenylalanine ammonia lyase (PAL) and peroxidases [59] as well as non-enzymatic antioxidants like total soluble sugar and proline to better tolerate stress have been observed, likely due to the increased concentration of ROS. Furthermore, Ghasempour et al [43] showed an increase in phenols, chlorophyll, flavonoids and alkaloids with plasma treatment. Pauzaite et al [23] has seen changes in flavonoids after plasma treatment while others have observed increased phenolic compounds [45,168,177].…”

“…The other genes that have been studied were by Guo et al [91] who observed an increase in LEA chaperone during stress, Ji et al [168] who saw increased expression of a hydrolytic enzyme called pullulanase in spinach seeds, Ghasempour et al [43] who saw an increase in gene expression for DAT, an enzyme in the biosynthesis of vinblastine and vincristine, alkaloids with anticancerous properties and Islam et al [64] who showed changes in gene expression of ascorbate peroxidase and catalase but not superoxide dismutase with an air plasma in rapeseed.…”

A Coaxial Dielectric Barrier Discharge Reactor for Treatment of Winter Wheat Seeds

“…It has been shown that exposure to plasma improves water uptake by the seed [34,37], decreases the contact angle of the seed surface [23,37], and functionalizes the seed coat by attaching new chemical bonds to the surface [34,38]. In addition to physical changes at the seed surface, physiological alterations along with effects on seedling growth and development [39,40] and improved tolerance against various stresses [11,41] have been observed as well. However, depending on the plasma source and treatment conditions, negative effects on germination and seedling growth are observed [39,42].…”

Seed Priming Technology as a Key Strategy to Increase Crop Plant Production under Adverse Environmental Conditions

“…Cold plasma priming involves the application of a mixture with ionized gas, positively charged particles, electrons, and neutral gas to seeds, which stimulates biological mechanism changes, such as the density of reactive oxygen species, phytohormone catabolism, reactive nitrogen species, and electrical conductivity 139,140 . According to several authors, in addition to eliminating phytopathogen contamination, this priming process also modifies the seed surface and facilitates the seed water uptake capacity, breaking dormancy and thus triggering modifications in hormones 133 , the proteome 141 , secondary metabolites 142 , and tissue differentiation 143 , leading to fast germination and better seedling growth and improving tolerance to environmental stress 133,137,139,140,144 .…”