MQTT Client through GSM for MCU (Microchip or Atmel) based microcontroller

I need someone to write a part of a firmware to integrate it in my main project for any microcontroller(PIC microchip or Atmel or in arduino IDE) to be able to receive serial data and publish them on a channel on the Webserver MQTT and the opposite (receive/subscribe data from a channel on Webserver MQTT) .

Serial Data baud rate:9600
Serial Data Type : String[200]