Silicon Regulates Source to Sink Metabolic Homeostasis and Promotes Growth of Rice Plants under Sulfur Deficiency

Abstract

Being an essential macroelement, sulfur (S) is pivotal for plant growth and development, and acute deficiency in this element leads to yield penalty. Since the last decade, strong evidence has reported the regulatory function of silicon (Si) in mitigating plant nutrient deficiency due to its significant diverse benefits on plant growth. However, the role of Si application in alleviating the negative impact of S deficiency is still obscure. In the present study, an attempt was undertaken to decipher the role of Si application on the metabolism of rice plants under S deficiency. The results showed a distinct transcriptomic and metabolic regulation in rice plants treated with Si under both short and long-term S deficiencies. The expression of Si transporters OsLsi1 and OsLsi2 was reduced under long-term deficiency, and the decrease was more pronounced when Si was provided. The expression of OsLsi6, which is involved in xylem loading of Si to shoots, was decreased under short-term S stress and remained unchanged in response to long-term stress. Moreover, the expression of S transporters OsSULTR tended to decrease by Si supply under short-term S deficiency but not under prolonged S stress. Si supply also reduced the level of almost all the metabolites in shoots of S-deficient plants, while it increased their level in the roots. The levels of stress-responsive hormones ABA, SA, and JA-lle were also decreased in shoots by Si application. Overall, our finding reveals the regulatory role of Si in modulating the metabolic homeostasis under S-deficient condition.

The Regulatory Role of Silicon in Mitigating Plant Nutritional Stresses

“…(d) Metabolite and hormonal profiling; metabolites and hormones are both vital for regulation of plant nutrition homeostasis. During the last few years, our research studies provided some evidence in this regard, indicating the impact of Si nutrition under K [ 49 ], S [ 54 , 55 ] and Mg [ 29 ] deficiencies. Moreover, the role of Si in metabolic changes under arsenic [ 98 ] as well as the change in amino acid levels in rice has been previously reported [ 99 ].…”

“…We have shown that, in barley plants subjected to osmotic stress and S deficiency simultaneously, Si modulated the genes involved in S and ABA homeostasis. Even though another stress trigger (osmotic stress) combined with S deficiency, nevertheless, this pioneering work could open the new windows to study deeply the cross talk between Si and S. Therefore, in our recent work, we attempted to decipher the role of Si application solely on the metabolism of Si-accumulator rice plants under S deficiency [ 55 ]. The study demonstrated a distinct source to sink metabolic regulation coupled with changes in the expression level of S and Si transporters leading to a consequent higher accumulation of Si and lower accumulation of stress phytohormones in the shoots, therefore maintaining plant growth and development under S deprivation [ 49 ].…”

Interactions of Silicon With Essential and Beneficial Elements in Plants

“…Work on interactions of Si with sulfur (S) is at a preliminary stage. Early results indicate that uptake and accumulation of S was unaffected by Si supply in forages crops ( Panicum maximum and Brachiaria ruziziensis × Brachiaria brizantha ) ( Buchelt et al, 2020 ) while Si supply even decreased shoot accumulation of S in barley and rice exposed to S deficiency ( Maillard et al, 2018 ; Réthoré et al, 2020 ). Molecular analysis also showed that the addition of Si tended to decrease transcript levels of S transporters (OsSULTR) in rice ( Réthoré et al, 2020 ; see Table 1 ).…”

K Deprivation Modulates the Primary Metabolites and Increases Putrescine Concentration in Brassica napus

“…Analysis of N was realized using an elemental FLASH 2000 CHNS analyzer (Thermo Fisher Scientific, Waltham, MA, United States) according to the instructions of the manufacturer from 2.5 mg of homogenized and lyophilized plant material. NH 4 + , NO 3 , and sulfate (SO 4 2– ) were extracted and analyzed according to Réthoré et al (2020) using high pressure ion chromatography with a conductivity detector (Dionex ICS5000 +, Thermo Fisher Scientific, Villebon-sur- Yvette, France).…”