Biochemical and Genetic Responses of Tea (Camellia sinensis (L.) Kuntze) Microplants under Mannitol-Induced Osmotic Stress In Vitro

Abstract

Osmotic stress is a major factor reducing the growth and yield of many horticultural crops worldwide. To reveal reliable markers of tolerant genotypes, we need a comprehensive understanding of the responsive mechanisms in crops. In vitro stress induction can be an efficient tool to study the mechanisms of responses in plants to help gain a better understanding of the physiological and genetic responses of plant tissues against each stress factor. In the present study, the osmotic stress was induced by addition of mannitol into the culture media to reveal biochemical and genetic responses of tea microplants. The contents of proline, threonine, epigallocatechin, and epigallocatechin gallate were increased in leaves during mannitol treatment. The expression level of several genes, namely DHN2, LOX1, LOX6, BAM, SUS1, TPS11, RS1, RS2, and SnRK1.3, was elevated by 2–10 times under mannitol-induced osmotic stress, while the expression of many other stress-related genes was not changed significantly. Surprisingly, down-regulation of the following genes, viz. bHLH12, bHLH7, bHLH21, bHLH43, CBF1, WRKY2, SWEET1, SWEET2, SWEET3, INV5, and LOX7, was observed. During this study, two major groups of highly correlated genes were observed. The first group included seven genes, namely CBF1, DHN3, HXK2,SnRK1.1, SPS, SWEET3, and SWEET1. The second group comprised eight genes, viz. DHN2, SnRK1.3, HXK3, RS1, RS2,LOX6, SUS4, and BAM5. A high level of correlation indicates the high strength connection of the genes which can be co-expressed or can be linked to the joint regulons. The present study demonstrates that tea plants develop several adaptations to cope under osmotic stress in vitro; however, some important stress-related genes were silent or downregulated in microplants.

In-Vitro Acclimatization of Curcuma Zedoaria Under Iso-Osmotic Treatments, Ex-Vitro Adaptation and Agronomic Traits in Greenhouse Conditions

“…One possible way of shoot and root initiation in Man culture media is to reduce IAA (indole-3-acetic acid) content to ensure down-regulation of expression levels of IAA-biosynthesis related gene(s) (Barbier et al 2015). Moreover, root and shoot traits of plantlets acclimatized under 2-3% Suc plus different degrees of Man were sharply decreased in relation to their concentrations in the culture medium (Custódio et al 2004;Madhulatha et al 2006;Samarina et al 2020). In Ruta graveolens, the growth performance and production of coumarins and rutin in the shoot cultures were regulated by 3% Suc + 1% Man in the culture medium (Mohamed and Ibrahim 2012).…”

“…In C. zedoaria, the morphological parameters, i.e., plant height, number of tillers, number of leaves, leaf length, leaf width, rhizome diameter, total rhizome weight and rhizome length as well as secondary metabolites in rhizome and leaf oil were nearly same in mother plant and in-vitro derived plants under eld trial (Jena et al 2020). In tea (Camelia sinensis), the major compounds, epigallocatechin and epigallocatechin gallate, in the fresh leaves of plantlets acclimated under 200 mM mannitol were enriched over control (Samarina et al 2020). Fresh mass, dry mass, number of shoots and COX1-inhibition activity (%) in plants of Eucomis autumnalis acclimatized under 4% Suc were increased when compared with low sucrose treatment (2%; w/v) (Taylor and van Staden 2001).…”

Tolerancia in vitro de cultivares de Rubus spp. a estrés hídrico simulado con manitol

“…El género Rubus es sensible a la sequía y los efectos del cambio climático puede tener un efecto negativo en este cultivo, que afecta la calidad y productividad de la fruta (Vergara et al, 2016). El estudio del uso de manitol en la inducción de estrés osmótico, produce una severidad específica por genotipo, la cual se evalúa de manera separada por cada especie (Samarina et al, 2020).…”

GENETIC MECHANISMS OF THE BIOSYNTHESIS OF CATECHINS, CAFFEINE AND L-THEANINE IN THE TEA PLANT Camellia sinensis (L.) Kuntze (review)

“…Вторичные метаболиты проявляют свойства адаптогенов, смягчая последствия стресса, который испытывают растения при воздействии высоких и низких температур (36)(37)(38)(39), ультрафиолетового облучения (40,41), осмотического шока in vitro (42)(43)(44), инфекции патогенов (45,46), минеральной недостаточности (47,32), уровня освещения и генетических факторов, других факторов (48)(49)(50)(51).…”