hrvatski

Uloga transportera HMA u akumulaciji Cd u vrsti Nicotiana glauca

Hyperaccumulation of toxic metals, such as Cd, is a rare phenomenon in plants. Nicotiana glauca is Cd-accumulating plant, while common tobacco N.tabacum is moderately tolerant non-accumulating plant. HMA metal transporters have been identified as key components of Cd accumulation and tolerance in other hyperaccumulator plants, such as Arabidopsis halleri and Nocacea caerulescens. Recently, HMA transporter genes have been sequenced in N.tabacum, but their localization and function are still not known. We have examined expression patterns of HMA-A and HMA-B genes in both species to clarify roles of these two transporters in Cd tolerance and accumulation. The difference among two tobacco species is important since they utilize vastly different tolerance mechanisms: Cd-hyperaccumulation (N.glauca) and Cd-exclusion strategy (N.tabacum). HMA-A was constitutively highly expressed in the leaves of N.glauca, and HMA-B was highly expressed in leaves and roots of N.tabacum. After Cd-treatment expression of both genes was induced in leaves and roots of N.glauca, while in N.tabacum induction was tissue specific: HMA-A in leaves and HMA-B in roots. Considering gene expression and Cd-accumulation phenotype in N.glauca, we propose that HMA-A is involved in metal root-to-shoot translocation, similar to its homologue in N.caerulescens (NcHMA4). On the other hand, HMA-B could be involved in Cd detoxication while transporting Cd into vacuoles, similar to another homologue in A.halleri (AhHMA3).

Nicotiana glauca; transporteri HMA; akumulacija Cd

nije evidentirano

engleski

Role of HMA transporters in Cd accumulation in Nicotiana glauca

Hyperaccumulation of toxic metals, such as Cd, is a rare phenomenon in plants. Nicotiana glauca is Cd-accumulating plant, while common tobacco N.tabacum is moderately tolerant non-accumulating plant. HMA metal transporters have been identified as key components of Cd accumulation and tolerance in other hyperaccumulator plants, such as Arabidopsis halleri and Nocacea caerulescens. Recently, HMA transporter genes have been sequenced in N.tabacum, but their localization and function are still not known. We have examined expression patterns of HMA-A and HMA-B genes in both species to clarify roles of these two transporters in Cd tolerance and accumulation. The difference among two tobacco species is important since they utilize vastly different tolerance mechanisms: Cd-hyperaccumulation (N.glauca) and Cd-exclusion strategy (N.tabacum). HMA-A was constitutively highly expressed in the leaves of N.glauca, and HMA-B was highly expressed in leaves and roots of N.tabacum. After Cd-treatment expression of both genes was induced in leaves and roots of N.glauca, while in N.tabacum induction was tissue specific: HMA-A in leaves and HMA-B in roots. Considering gene expression and Cd-accumulation phenotype in N.glauca, we propose that HMA-A is involved in metal root-to-shoot translocation, similar to its homologue in N.caerulescens (NcHMA4). On the other hand, HMA-B could be involved in Cd detoxication while transporting Cd into vacuoles, similar to another homologue in A.halleri (AhHMA3).

Nicotiana glauca; HMA transporters; Cd accumulation

nije evidentirano