How to read serial by PyQt5

By using PyQt5 I made a window with a simple label, I want to read data by pyserial and replace the label text when the python program start without clicking on any button. could you please let me know how can I do that?

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(666, 577)
        Form.setLayoutDirection(QtCore.Qt.LeftToRight)
        Form.setStyleSheet("background-color: rgb(0, 0, 0);\n"
"color: #FFF;")
        self.formLayout = QtWidgets.QFormLayout(Form)
        self.formLayout.setObjectName("formLayout")
        self.gridLayout = QtWidgets.QGridLayout()
        self.gridLayout.setObjectName("gridLayout")
        self.Title = QtWidgets.QLabel(Form)
        font = QtGui.QFont()
        font.setPointSize(60)
        self.Title.setFont(font)
        self.Title.setAlignment(QtCore.Qt.AlignHCenter|QtCore.Qt.AlignTop)
        self.Title.setObjectName("Title")
        self.gridLayout.addWidget(self.Title, 3, 1, 1, 1)
        self.formLayout.setLayout(1, QtWidgets.QFormLayout.FieldRole, self.gridLayout)

        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.Title.setText(_translate("Form", "text"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Form = QtWidgets.QWidget()
    ui = Ui_Form()
    ui.setupUi(Form)
    Form.show()
    sys.exit(app.exec_())